diff --git a/scripts/Deploy-MSBuild.ps1 b/scripts/Deploy-MSBuild.ps1
index b7bf08ced01..c9bc90217fe 100644
--- a/scripts/Deploy-MSBuild.ps1
+++ b/scripts/Deploy-MSBuild.ps1
@@ -74,11 +74,11 @@ $filesToCopyToBin = @(
     FileToCopy "$bootstrapBinDirectory\Microsoft.Managed.targets"
     FileToCopy "$bootstrapBinDirectory\Microsoft.Managed.Before.targets"
     FileToCopy "$bootstrapBinDirectory\Microsoft.Managed.After.targets"
-    FileToCopy "$bootstrapBinDirectory\Microsoft.Net.props"
-    FileToCopy "$bootstrapBinDirectory\Microsoft.NetFramework.CurrentVersion.props"
-    FileToCopy "$bootstrapBinDirectory\Microsoft.NetFramework.CurrentVersion.targets"
-    FileToCopy "$bootstrapBinDirectory\Microsoft.NetFramework.props"
-    FileToCopy "$bootstrapBinDirectory\Microsoft.NetFramework.targets"
+    FileToCopy "$bootstrapBinDirectory\Microsoft.NET.props"
+    FileToCopy "$bootstrapBinDirectory\Microsoft.NETFramework.CurrentVersion.props"
+    FileToCopy "$bootstrapBinDirectory\Microsoft.NETFramework.CurrentVersion.targets"
+    FileToCopy "$bootstrapBinDirectory\Microsoft.NETFramework.props"
+    FileToCopy "$bootstrapBinDirectory\Microsoft.NETFramework.targets"
     FileToCopy "$bootstrapBinDirectory\Microsoft.VisualBasic.CrossTargeting.targets"
     FileToCopy "$bootstrapBinDirectory\Microsoft.VisualBasic.CurrentVersion.targets"
     FileToCopy "$bootstrapBinDirectory\Microsoft.VisualBasic.targets"
diff --git a/src/Build/BackEnd/BuildManager/BuildManager.cs b/src/Build/BackEnd/BuildManager/BuildManager.cs
index e071160c912..271454fb2a9 100644
--- a/src/Build/BackEnd/BuildManager/BuildManager.cs
+++ b/src/Build/BackEnd/BuildManager/BuildManager.cs
@@ -629,7 +629,7 @@ void Callback(object state)
                         }
                     }
 
-                    ShutdownConnectedNodesAsync(true /* abort */);
+                    ShutdownConnectedNodes(true /* abort */);
                     CheckForActiveNodesAndCleanUpSubmissions();
                 }
             }
@@ -774,7 +774,7 @@ public void EndBuild()
             try
             {
                 _noActiveSubmissionsEvent.WaitOne();
-                ShutdownConnectedNodesAsync(false /* normal termination */);
+                ShutdownConnectedNodes(false /* normal termination */);
                 _noNodesActiveEvent.WaitOne();
 
                 // Wait for all of the actions in the work queue to drain.  Wait() could throw here if there was an unhandled exception
@@ -1955,7 +1955,7 @@ public void Dispose()
         /// Asks the nodeManager to tell the currently connected nodes to shut down and sets a flag preventing all non-shutdown-related packets from
         /// being processed.
         /// </summary>
-        private void ShutdownConnectedNodesAsync(bool abort)
+        private void ShutdownConnectedNodes(bool abort)
         {
             _shuttingDown = true;
 
diff --git a/src/Build/BackEnd/Components/Communications/NodeProviderOutOfProcBase.cs b/src/Build/BackEnd/Components/Communications/NodeProviderOutOfProcBase.cs
index 501d9ddbbc8..0889994b493 100644
--- a/src/Build/BackEnd/Components/Communications/NodeProviderOutOfProcBase.cs
+++ b/src/Build/BackEnd/Components/Communications/NodeProviderOutOfProcBase.cs
@@ -25,6 +25,10 @@
 using Microsoft.Build.Utilities;
 
 using BackendNativeMethods = Microsoft.Build.BackEnd.NativeMethods;
+using Task = System.Threading.Tasks.Task;
+using DotNetFrameworkArchitecture = Microsoft.Build.Shared.DotNetFrameworkArchitecture;
+using Microsoft.Build.Framework;
+using Microsoft.Build.BackEnd.Logging;
 
 namespace Microsoft.Build.BackEnd
 {
@@ -49,6 +53,11 @@ internal abstract class NodeProviderOutOfProcBase
         /// </summary>
         private const int TimeoutForNewNodeCreation = 30000;
 
+        /// <summary>
+        /// The amount of time to wait for an out-of-proc node to exit.
+        /// </summary>
+        private const int TimeoutForWaitForExit = 30000;
+
         /// <summary>
         /// The build component host.
         /// </summary>
@@ -95,9 +104,30 @@ protected void ShutdownConnectedNodes(List<NodeContext> contextsToShutDown, bool
             // Send the build completion message to the nodes, causing them to shutdown or reset.
             _processesToIgnore.Clear();
 
+            // We wait for child nodes to exit to avoid them changing the terminal
+            // after this process terminates.
+            bool waitForExit =  !enableReuse &&
+                                !Console.IsInputRedirected &&
+                                Traits.Instance.EscapeHatches.EnsureStdOutForChildNodesIsPrimaryStdout;
+
+            Task[] waitForExitTasks = waitForExit && contextsToShutDown.Count > 0 ? new Task[contextsToShutDown.Count] : null;
+            int i = 0;
+            var loggingService = _componentHost.LoggingService;
             foreach (NodeContext nodeContext in contextsToShutDown)
             {
-                nodeContext?.SendData(new NodeBuildComplete(enableReuse));
+                if (nodeContext is null)
+                {
+                    continue;
+                }
+                nodeContext.SendData(new NodeBuildComplete(enableReuse));
+                if (waitForExit)
+                {
+                    waitForExitTasks[i++] = nodeContext.WaitForExitAsync(loggingService);
+                }
+            }
+            if (waitForExitTasks != null)
+            {
+                Task.WaitAll(waitForExitTasks);
             }
         }
 
@@ -138,7 +168,7 @@ protected void ShutdownAllNodes(bool nodeReuse, NodeContextTerminateDelegate ter
                 {
                     // If we're able to connect to such a process, send a packet requesting its termination
                     CommunicationsUtilities.Trace("Shutting down node with pid = {0}", nodeProcess.Id);
-                    NodeContext nodeContext = new NodeContext(0, nodeProcess.Id, nodeStream, factory, terminateNode);
+                    NodeContext nodeContext = new NodeContext(0, nodeProcess, nodeStream, factory, terminateNode);
                     nodeContext.SendData(new NodeBuildComplete(false /* no node reuse */));
                     nodeStream.Dispose();
                 }
@@ -204,7 +234,7 @@ protected NodeContext GetNode(string msbuildLocation, string commandLineArgs, in
                     {
                         // Connection successful, use this node.
                         CommunicationsUtilities.Trace("Successfully connected to existed node {0} which is PID {1}", nodeId, nodeProcess.Id);
-                        return new NodeContext(nodeId, nodeProcess.Id, nodeStream, factory, terminateNode);
+                        return new NodeContext(nodeId, nodeProcess, nodeStream, factory, terminateNode);
                     }
                 }
             }
@@ -242,20 +272,20 @@ protected NodeContext GetNode(string msbuildLocation, string commandLineArgs, in
 #endif
 
                 // Create the node process
-                int msbuildProcessId = LaunchNode(msbuildLocation, commandLineArgs);
-                _processesToIgnore.Add(GetProcessesToIgnoreKey(hostHandshake, msbuildProcessId));
+                Process msbuildProcess = LaunchNode(msbuildLocation, commandLineArgs);
+                _processesToIgnore.Add(GetProcessesToIgnoreKey(hostHandshake, msbuildProcess.Id));
 
                 // Note, when running under IMAGEFILEEXECUTIONOPTIONS registry key to debug, the process ID
                 // gotten back from CreateProcess is that of the debugger, which causes this to try to connect
                 // to the debugger process. Instead, use MSBUILDDEBUGONSTART=1
 
                 // Now try to connect to it.
-                Stream nodeStream = TryConnectToProcess(msbuildProcessId, TimeoutForNewNodeCreation, hostHandshake);
+                Stream nodeStream = TryConnectToProcess(msbuildProcess.Id, TimeoutForNewNodeCreation, hostHandshake);
                 if (nodeStream != null)
                 {
                     // Connection successful, use this node.
-                    CommunicationsUtilities.Trace("Successfully connected to created node {0} which is PID {1}", nodeId, msbuildProcessId);
-                    return new NodeContext(nodeId, msbuildProcessId, nodeStream, factory, terminateNode);
+                    CommunicationsUtilities.Trace("Successfully connected to created node {0} which is PID {1}", nodeId, msbuildProcess.Id);
+                    return new NodeContext(nodeId, msbuildProcess, nodeStream, factory, terminateNode);
                 }
             }
 
@@ -391,7 +421,7 @@ private Stream TryConnectToProcess(int nodeProcessId, int timeout, Handshake han
         /// <summary>
         /// Creates a new MSBuild process
         /// </summary>
-        private int LaunchNode(string msbuildLocation, string commandLineArgs)
+        private Process LaunchNode(string msbuildLocation, string commandLineArgs)
         {
             // Should always have been set already.
             ErrorUtilities.VerifyThrowInternalLength(msbuildLocation, nameof(msbuildLocation));
@@ -490,7 +520,7 @@ private int LaunchNode(string msbuildLocation, string commandLineArgs)
                 }
 
                 CommunicationsUtilities.Trace("Successfully launched {1} node with PID {0}", process.Id, exeName);
-                return process.Id;
+                return process;
             }
             else
             {
@@ -548,7 +578,7 @@ out processInfo
                 }
 
                 CommunicationsUtilities.Trace("Successfully launched {1} node with PID {0}", childProcessId, exeName);
-                return childProcessId;
+                return Process.GetProcessById(childProcessId);
             }
         }
 
@@ -582,6 +612,13 @@ private static string GetCurrentHost()
         /// </summary>
         internal class NodeContext
         {
+            enum ExitPacketState
+            {
+                None,
+                ExitPacketQueued,
+                ExitPacketSent
+            }
+
             // The pipe(s) used to communicate with the node.
             private Stream _clientToServerStream;
             private Stream _serverToClientStream;
@@ -597,9 +634,9 @@ internal class NodeContext
             private int _nodeId;
 
             /// <summary>
-            /// The process id
+            /// The node process.
             /// </summary>
-            private int _processId;
+            private readonly Process _process;
 
             /// <summary>
             /// An array used to store the header byte for each packet when read.
@@ -631,14 +668,14 @@ internal class NodeContext
             private Task _packetWriteDrainTask = Task.CompletedTask;
 
             /// <summary>
-            /// Event indicating the node has terminated.
+            /// Delegate called when the context terminates.
             /// </summary>
-            private ManualResetEvent _nodeTerminated;
+            private NodeContextTerminateDelegate _terminateDelegate;
 
             /// <summary>
-            /// Delegate called when the context terminates.
+            /// Tracks the state of the packet sent to terminate the node.
             /// </summary>
-            private NodeContextTerminateDelegate _terminateDelegate;
+            private ExitPacketState _exitPacketState;
 
             /// <summary>
             /// Per node read buffers
@@ -648,20 +685,18 @@ internal class NodeContext
             /// <summary>
             /// Constructor.
             /// </summary>
-            public NodeContext(int nodeId, int processId,
+            public NodeContext(int nodeId, Process process,
                 Stream nodePipe,
                 INodePacketFactory factory, NodeContextTerminateDelegate terminateDelegate)
             {
                 _nodeId = nodeId;
-                _processId = processId;
+                _process = process;
                 _clientToServerStream = nodePipe;
                 _serverToClientStream = nodePipe;
                 _packetFactory = factory;
                 _headerByte = new byte[5]; // 1 for the packet type, 4 for the body length
-
                 _readBufferMemoryStream = new MemoryStream();
                 _writeBufferMemoryStream = new MemoryStream();
-                _nodeTerminated = new ManualResetEvent(false);
                 _terminateDelegate = terminateDelegate;
                 _sharedReadBuffer = InterningBinaryReader.CreateSharedBuffer();
             }
@@ -749,6 +784,10 @@ public async Task RunPacketReadLoopAsync()
             /// <param name="packet">The packet to send.</param>
             public void SendData(INodePacket packet)
             {
+                if (IsExitPacket(packet))
+                {
+                    _exitPacketState = ExitPacketState.ExitPacketQueued;
+                }
                 _packetWriteQueue.Add(packet);
                 DrainPacketQueue();
             }
@@ -816,6 +855,10 @@ private void SendDataCore(INodePacket packet)
                         int lengthToWrite = Math.Min(writeStreamLength - i, MaxPacketWriteSize);
                         _serverToClientStream.Write(writeStreamBuffer, i, lengthToWrite);
                     }
+                    if (IsExitPacket(packet))
+                    {
+                        _exitPacketState = ExitPacketState.ExitPacketSent;
+                    }
                 }
                 catch (IOException e)
                 {
@@ -828,6 +871,11 @@ private void SendDataCore(INodePacket packet)
                 }
             }
 
+            private static bool IsExitPacket(INodePacket packet)
+            {
+                return packet is NodeBuildComplete buildCompletePacket && !buildCompletePacket.PrepareForReuse;
+            }
+
             /// <summary>
             /// Avoid having a BinaryWriter just to write a 4-byte int
             /// </summary>
@@ -842,7 +890,7 @@ private void WriteInt32(MemoryStream stream, int value)
             /// <summary>
             /// Closes the node's context, disconnecting it from the node.
             /// </summary>
-            public void Close()
+            private void Close()
             {
                 _clientToServerStream.Dispose();
                 if (!object.ReferenceEquals(_clientToServerStream, _serverToClientStream))
@@ -852,6 +900,52 @@ public void Close()
                 _terminateDelegate(_nodeId);
             }
 
+            /// <summary>
+            /// Waits for the child node process to exit.
+            /// </summary>
+            public async Task WaitForExitAsync(ILoggingService loggingService)
+            {
+                if (_exitPacketState == ExitPacketState.ExitPacketQueued)
+                {
+                    // Wait up to 100ms until all remaining packets are sent.
+                    // We don't need to wait long, just long enough for the Task to start running on the ThreadPool.
+                    await Task.WhenAny(_packetWriteDrainTask, Task.Delay(100));
+                }
+                if (_exitPacketState == ExitPacketState.ExitPacketSent)
+                {
+                    CommunicationsUtilities.Trace("Waiting for node with pid = {0} to exit", _process.Id);
+
+                    // .NET 5 introduces a real WaitForExitAsyc.
+                    // This is a poor man's implementation that uses polling.
+                    int timeout = TimeoutForWaitForExit;
+                    int delay = 5;
+                    while (timeout > 0)
+                    {
+                        bool exited = _process.WaitForExit(milliseconds: 0);
+                        if (exited)
+                        {
+                            return;
+                        }
+                        timeout -= delay;
+                        await Task.Delay(delay).ConfigureAwait(false);
+
+                        // Double delay up to 500ms.
+                        delay = Math.Min(delay * 2, 500);
+                    }
+                }
+
+                // Kill the child and do a blocking wait.
+                loggingService?.LogWarning(
+                    BuildEventContext.Invalid,
+                    null,
+                    BuildEventFileInfo.Empty,
+                    "KillingProcessWithPid",
+                    _process.Id);
+                CommunicationsUtilities.Trace("Killing node with pid = {0}", _process.Id);
+
+                _process.KillTree(timeout: 5000);
+            }
+
 #if FEATURE_APM
             /// <summary>
             /// Completes the asynchronous packet write to the node.
@@ -873,17 +967,16 @@ private bool ProcessHeaderBytesRead(int bytesRead)
             {
                 if (bytesRead != _headerByte.Length)
                 {
-                    CommunicationsUtilities.Trace(_nodeId, "COMMUNICATIONS ERROR (HRC) Node: {0} Process: {1} Bytes Read: {2} Expected: {3}", _nodeId, _processId, bytesRead, _headerByte.Length);
+                    CommunicationsUtilities.Trace(_nodeId, "COMMUNICATIONS ERROR (HRC) Node: {0} Process: {1} Bytes Read: {2} Expected: {3}", _nodeId, _process.Id, bytesRead, _headerByte.Length);
                     try
                     {
-                        Process childProcess = Process.GetProcessById(_processId);
-                        if (childProcess?.HasExited != false)
+                        if (_process.HasExited)
                         {
-                            CommunicationsUtilities.Trace(_nodeId, "   Child Process {0} has exited.", _processId);
+                            CommunicationsUtilities.Trace(_nodeId, "   Child Process {0} has exited.", _process.Id);
                         }
                         else
                         {
-                            CommunicationsUtilities.Trace(_nodeId, "   Child Process {0} is still running.", _processId);
+                            CommunicationsUtilities.Trace(_nodeId, "   Child Process {0} is still running.", _process.Id);
                         }
                     }
                     catch (Exception e) when (!ExceptionHandling.IsCriticalException(e))
diff --git a/src/Build/BackEnd/TaskExecutionHost/TaskExecutionHost.cs b/src/Build/BackEnd/TaskExecutionHost/TaskExecutionHost.cs
index 9a329a707b5..7bf9a69aebc 100644
--- a/src/Build/BackEnd/TaskExecutionHost/TaskExecutionHost.cs
+++ b/src/Build/BackEnd/TaskExecutionHost/TaskExecutionHost.cs
@@ -24,6 +24,7 @@
 using Microsoft.Build.Utilities;
 
 using TaskItem = Microsoft.Build.Execution.ProjectItemInstance.TaskItem;
+using Task = System.Threading.Tasks.Task;
 
 namespace Microsoft.Build.BackEnd
 {
diff --git a/src/Build/Microsoft.Build.csproj b/src/Build/Microsoft.Build.csproj
index 6989f8cc24d..d71f127c265 100644
--- a/src/Build/Microsoft.Build.csproj
+++ b/src/Build/Microsoft.Build.csproj
@@ -127,6 +127,7 @@
     <Compile Include="..\Shared\NodeBuildComplete.cs" />
     <Compile Include="..\Shared\NodeShutdown.cs" />
     <Compile Include="..\Shared\NamedPipeUtil.cs" />
+    <Compile Include="..\Shared\ProcessExtensions.cs" />
     <Compile Include="..\Shared\TaskLoggingHelper.cs">
       <Link>BackEnd\Components\RequestBuilder\IntrinsicTasks\TaskLoggingHelper.cs</Link>
       <ExcludeFromStyleCop>True</ExcludeFromStyleCop>
diff --git a/src/Build/Resources/Strings.resx b/src/Build/Resources/Strings.resx
index 5b737e6d5f0..9946e751fed 100644
--- a/src/Build/Resources/Strings.resx
+++ b/src/Build/Resources/Strings.resx
@@ -1876,4 +1876,7 @@ Utilization:          {0} Average Utilization: {1:###.0}</value>
   <data name="NoProjectCachePluginFoundInAssembly" xml:space="preserve">
     <value>MSB4270: No project cache plugins found in assembly "{0}". Expected one.</value>
   </data>
+  <data name="KillingProcessWithPid" xml:space="preserve">
+    <value>Killing process with pid = {0}.</value>
+  </data>
 </root>
diff --git a/src/Build/Resources/xlf/Strings.cs.xlf b/src/Build/Resources/xlf/Strings.cs.xlf
index 157443afc16..2153f0e22a1 100644
--- a/src/Build/Resources/xlf/Strings.cs.xlf
+++ b/src/Build/Resources/xlf/Strings.cs.xlf
@@ -132,6 +132,11 @@
         <target state="needs-review-translation">Objekty EvaluationContext vytvořené pomocí SharingPolicy.Isolated nepodporují předávání souborového systému MSBuildFileSystemBase.</target>
         <note />
       </trans-unit>
+      <trans-unit id="KillingProcessWithPid">
+        <source>Killing process with pid = {0}.</source>
+        <target state="new">Killing process with pid = {0}.</target>
+        <note />
+      </trans-unit>
       <trans-unit id="LoadingProjectCachePlugin">
         <source>"Loading the following project cache plugin:
     {0}"</source>
diff --git a/src/Build/Resources/xlf/Strings.de.xlf b/src/Build/Resources/xlf/Strings.de.xlf
index 895d6839645..d864f0a20f2 100644
--- a/src/Build/Resources/xlf/Strings.de.xlf
+++ b/src/Build/Resources/xlf/Strings.de.xlf
@@ -132,6 +132,11 @@
         <target state="needs-review-translation">"Die Übergabe eines MSBuildFileSystemBase-Dateisystems wird von EvaluationContext-Objekten, die mit SharingPolicy.Isolated erstellt wurden, nicht unterstützt."</target>
         <note />
       </trans-unit>
+      <trans-unit id="KillingProcessWithPid">
+        <source>Killing process with pid = {0}.</source>
+        <target state="new">Killing process with pid = {0}.</target>
+        <note />
+      </trans-unit>
       <trans-unit id="LoadingProjectCachePlugin">
         <source>"Loading the following project cache plugin:
     {0}"</source>
diff --git a/src/Build/Resources/xlf/Strings.en.xlf b/src/Build/Resources/xlf/Strings.en.xlf
index 444ca3a5542..1254d414831 100644
--- a/src/Build/Resources/xlf/Strings.en.xlf
+++ b/src/Build/Resources/xlf/Strings.en.xlf
@@ -132,6 +132,11 @@
         <target state="new">EvaluationContext objects created with SharingPolicy.Isolated do not support being passed an MSBuildFileSystemBase file system.</target>
         <note />
       </trans-unit>
+      <trans-unit id="KillingProcessWithPid">
+        <source>Killing process with pid = {0}.</source>
+        <target state="new">Killing process with pid = {0}.</target>
+        <note />
+      </trans-unit>
       <trans-unit id="LoadingProjectCachePlugin">
         <source>"Loading the following project cache plugin:
     {0}"</source>
diff --git a/src/Build/Resources/xlf/Strings.es.xlf b/src/Build/Resources/xlf/Strings.es.xlf
index 36a2729aa8b..99441e2fb4f 100644
--- a/src/Build/Resources/xlf/Strings.es.xlf
+++ b/src/Build/Resources/xlf/Strings.es.xlf
@@ -132,6 +132,11 @@
         <target state="needs-review-translation">"Los objetos EvaluationContext creados con SharingPolicy.Isolated no admiten que se les pase un sistema de archivos MSBuildFileSystemBase".</target>
         <note />
       </trans-unit>
+      <trans-unit id="KillingProcessWithPid">
+        <source>Killing process with pid = {0}.</source>
+        <target state="new">Killing process with pid = {0}.</target>
+        <note />
+      </trans-unit>
       <trans-unit id="LoadingProjectCachePlugin">
         <source>"Loading the following project cache plugin:
     {0}"</source>
diff --git a/src/Build/Resources/xlf/Strings.fr.xlf b/src/Build/Resources/xlf/Strings.fr.xlf
index 26c0b149b57..a19de6cd10b 100644
--- a/src/Build/Resources/xlf/Strings.fr.xlf
+++ b/src/Build/Resources/xlf/Strings.fr.xlf
@@ -132,6 +132,11 @@
         <target state="needs-review-translation">"Les objets EvaluationContext créés avec SharingPolicy.Isolated ne prennent pas en charge le passage d'un système de fichiers MSBuildFileSystemBase."</target>
         <note />
       </trans-unit>
+      <trans-unit id="KillingProcessWithPid">
+        <source>Killing process with pid = {0}.</source>
+        <target state="new">Killing process with pid = {0}.</target>
+        <note />
+      </trans-unit>
       <trans-unit id="LoadingProjectCachePlugin">
         <source>"Loading the following project cache plugin:
     {0}"</source>
diff --git a/src/Build/Resources/xlf/Strings.it.xlf b/src/Build/Resources/xlf/Strings.it.xlf
index 86a00974a5f..eddf911a5ef 100644
--- a/src/Build/Resources/xlf/Strings.it.xlf
+++ b/src/Build/Resources/xlf/Strings.it.xlf
@@ -132,6 +132,11 @@
         <target state="needs-review-translation">"Agli oggetti EvaluationContext creati con SharingPolicy.Isolated non è possibile passare un file system MSBuildFileSystemBase."</target>
         <note />
       </trans-unit>
+      <trans-unit id="KillingProcessWithPid">
+        <source>Killing process with pid = {0}.</source>
+        <target state="new">Killing process with pid = {0}.</target>
+        <note />
+      </trans-unit>
       <trans-unit id="LoadingProjectCachePlugin">
         <source>"Loading the following project cache plugin:
     {0}"</source>
diff --git a/src/Build/Resources/xlf/Strings.ja.xlf b/src/Build/Resources/xlf/Strings.ja.xlf
index 27c3d3f6130..ee8252b9dcd 100644
--- a/src/Build/Resources/xlf/Strings.ja.xlf
+++ b/src/Build/Resources/xlf/Strings.ja.xlf
@@ -132,6 +132,11 @@
         <target state="needs-review-translation">"SharingPolicy.Isolated を指定して作成された EvaluationContext オブジェクトに MSBuildFileSystemBase ファイル システムを渡すことはサポートされていません。"</target>
         <note />
       </trans-unit>
+      <trans-unit id="KillingProcessWithPid">
+        <source>Killing process with pid = {0}.</source>
+        <target state="new">Killing process with pid = {0}.</target>
+        <note />
+      </trans-unit>
       <trans-unit id="LoadingProjectCachePlugin">
         <source>"Loading the following project cache plugin:
     {0}"</source>
diff --git a/src/Build/Resources/xlf/Strings.ko.xlf b/src/Build/Resources/xlf/Strings.ko.xlf
index 367cf54895e..14e55b6f38f 100644
--- a/src/Build/Resources/xlf/Strings.ko.xlf
+++ b/src/Build/Resources/xlf/Strings.ko.xlf
@@ -132,6 +132,11 @@
         <target state="needs-review-translation">"SharingPolicy.Isolated로 만든 EvaluationContext 개체는 MSBuildFileSystemBase 파일 시스템 전달을 지원하지 않습니다."</target>
         <note />
       </trans-unit>
+      <trans-unit id="KillingProcessWithPid">
+        <source>Killing process with pid = {0}.</source>
+        <target state="new">Killing process with pid = {0}.</target>
+        <note />
+      </trans-unit>
       <trans-unit id="LoadingProjectCachePlugin">
         <source>"Loading the following project cache plugin:
     {0}"</source>
diff --git a/src/Build/Resources/xlf/Strings.pl.xlf b/src/Build/Resources/xlf/Strings.pl.xlf
index b13eb7e424f..4b42a435adb 100644
--- a/src/Build/Resources/xlf/Strings.pl.xlf
+++ b/src/Build/Resources/xlf/Strings.pl.xlf
@@ -132,6 +132,11 @@
         <target state="needs-review-translation">„Obiekty EvaluationContext utworzone za pomocą elementu SharingPolicy.Isolated nie obsługują przekazywania za pomocą systemu plików MSBuildFileSystemBase.”</target>
         <note />
       </trans-unit>
+      <trans-unit id="KillingProcessWithPid">
+        <source>Killing process with pid = {0}.</source>
+        <target state="new">Killing process with pid = {0}.</target>
+        <note />
+      </trans-unit>
       <trans-unit id="LoadingProjectCachePlugin">
         <source>"Loading the following project cache plugin:
     {0}"</source>
diff --git a/src/Build/Resources/xlf/Strings.pt-BR.xlf b/src/Build/Resources/xlf/Strings.pt-BR.xlf
index 188df5f9cf3..edf8687b3cf 100644
--- a/src/Build/Resources/xlf/Strings.pt-BR.xlf
+++ b/src/Build/Resources/xlf/Strings.pt-BR.xlf
@@ -132,6 +132,11 @@
         <target state="needs-review-translation">"Os objetos EvaluationContext criados com SharingPolicy.Isolable não são compatíveis com o recebimento de um sistema de arquivos MSBuildFileSystemBase."</target>
         <note />
       </trans-unit>
+      <trans-unit id="KillingProcessWithPid">
+        <source>Killing process with pid = {0}.</source>
+        <target state="new">Killing process with pid = {0}.</target>
+        <note />
+      </trans-unit>
       <trans-unit id="LoadingProjectCachePlugin">
         <source>"Loading the following project cache plugin:
     {0}"</source>
diff --git a/src/Build/Resources/xlf/Strings.ru.xlf b/src/Build/Resources/xlf/Strings.ru.xlf
index 508d9a08b28..5e51ed494ea 100644
--- a/src/Build/Resources/xlf/Strings.ru.xlf
+++ b/src/Build/Resources/xlf/Strings.ru.xlf
@@ -132,6 +132,11 @@
         <target state="needs-review-translation">"Объекты EvaluationContext, созданные с помощью SharingPolicy.Isolated, не поддерживают передачу в файловую систему MSBuildFileSystemBase."</target>
         <note />
       </trans-unit>
+      <trans-unit id="KillingProcessWithPid">
+        <source>Killing process with pid = {0}.</source>
+        <target state="new">Killing process with pid = {0}.</target>
+        <note />
+      </trans-unit>
       <trans-unit id="LoadingProjectCachePlugin">
         <source>"Loading the following project cache plugin:
     {0}"</source>
diff --git a/src/Build/Resources/xlf/Strings.tr.xlf b/src/Build/Resources/xlf/Strings.tr.xlf
index 9bcd9bde59b..9e3d3c7c50c 100644
--- a/src/Build/Resources/xlf/Strings.tr.xlf
+++ b/src/Build/Resources/xlf/Strings.tr.xlf
@@ -132,6 +132,11 @@
         <target state="needs-review-translation">"SharingPolicy.Isolated ile oluşturulan EvaluationContext nesneleri bir MSBuildFileSystemBase dosya sisteminin geçirilmesini desteklemez."</target>
         <note />
       </trans-unit>
+      <trans-unit id="KillingProcessWithPid">
+        <source>Killing process with pid = {0}.</source>
+        <target state="new">Killing process with pid = {0}.</target>
+        <note />
+      </trans-unit>
       <trans-unit id="LoadingProjectCachePlugin">
         <source>"Loading the following project cache plugin:
     {0}"</source>
diff --git a/src/Build/Resources/xlf/Strings.zh-Hans.xlf b/src/Build/Resources/xlf/Strings.zh-Hans.xlf
index 942ffe8d692..9a69ab3846e 100644
--- a/src/Build/Resources/xlf/Strings.zh-Hans.xlf
+++ b/src/Build/Resources/xlf/Strings.zh-Hans.xlf
@@ -132,6 +132,11 @@
         <target state="needs-review-translation">“使用 SharingPolicy.Isolated 创建的 EvaluationContext 对象不支持通过 MSBuildFileSystemBase 文件系统传递。”</target>
         <note />
       </trans-unit>
+      <trans-unit id="KillingProcessWithPid">
+        <source>Killing process with pid = {0}.</source>
+        <target state="new">Killing process with pid = {0}.</target>
+        <note />
+      </trans-unit>
       <trans-unit id="LoadingProjectCachePlugin">
         <source>"Loading the following project cache plugin:
     {0}"</source>
diff --git a/src/Build/Resources/xlf/Strings.zh-Hant.xlf b/src/Build/Resources/xlf/Strings.zh-Hant.xlf
index eadd2f2e6cc..e6a19c0a9c3 100644
--- a/src/Build/Resources/xlf/Strings.zh-Hant.xlf
+++ b/src/Build/Resources/xlf/Strings.zh-Hant.xlf
@@ -132,6 +132,11 @@
         <target state="needs-review-translation">"使用 SharingPolicy.Isolated 建立的 EvaluationContext 物件不支援以 MSBuildFileSystemBase 檔案系統傳遞。"</target>
         <note />
       </trans-unit>
+      <trans-unit id="KillingProcessWithPid">
+        <source>Killing process with pid = {0}.</source>
+        <target state="new">Killing process with pid = {0}.</target>
+        <note />
+      </trans-unit>
       <trans-unit id="LoadingProjectCachePlugin">
         <source>"Loading the following project cache plugin:
     {0}"</source>
diff --git a/src/Shared/NativeMethodsShared.cs b/src/Shared/NativeMethodsShared.cs
index 4818d7eda9c..42e8a3ead07 100644
--- a/src/Shared/NativeMethodsShared.cs
+++ b/src/Shared/NativeMethodsShared.cs
@@ -465,10 +465,8 @@ public SystemInformationData()
                                 string arch = null;
                                 if (proc != null)
                                 {
-                                    // Since uname -m simply returns kernel property, it should be quick.
-                                    // 1 second is the best guess for a safe timeout.
-                                    proc.WaitForExit(1000);
                                     arch = proc.StandardOutput.ReadLine();
+                                    proc.WaitForExit();
                                 }
 
                                 if (!string.IsNullOrEmpty(arch))
diff --git a/src/Utilities/ProcessExtensions.cs b/src/Shared/ProcessExtensions.cs
similarity index 78%
rename from src/Utilities/ProcessExtensions.cs
rename to src/Shared/ProcessExtensions.cs
index 04d6afb3f36..9504440d124 100644
--- a/src/Utilities/ProcessExtensions.cs
+++ b/src/Shared/ProcessExtensions.cs
@@ -7,7 +7,7 @@
 using System.IO;
 using Microsoft.Build.Shared;
 
-namespace Microsoft.Build.Utilities
+namespace Microsoft.Build.Shared
 {
     internal static class ProcessExtensions
     {
@@ -46,12 +46,12 @@ public static void KillTree(this Process process, int timeout)
 
         private static void GetAllChildIdsUnix(int parentId, ISet<int> children)
         {
-            var exitCode = RunProcessAndWaitForExit(
+            RunProcessAndWaitForExit(
                 "pgrep",
                 $"-P {parentId}",
                 out string stdout);
 
-            if (exitCode == 0 && !string.IsNullOrEmpty(stdout))
+            if (!string.IsNullOrEmpty(stdout))
             {
                 using (var reader = new StringReader(stdout))
                 {
@@ -77,13 +77,24 @@ private static void GetAllChildIdsUnix(int parentId, ISet<int> children)
 
         private static void KillProcessUnix(int processId)
         {
-            RunProcessAndWaitForExit(
-                "kill",
-                $"-TERM {processId}",
-                out string _);
+            try
+            {
+                using Process process = Process.GetProcessById(processId);
+                process.Kill();
+            }
+            catch (ArgumentException)
+            {
+                // Process already terminated.
+                return;
+            }
+            catch (InvalidOperationException)
+            {
+                // Process already terminated.
+                return;
+            }
         }
 
-        private static int RunProcessAndWaitForExit(string fileName, string arguments, out string stdout)
+        private static void RunProcessAndWaitForExit(string fileName, string arguments, out string stdout)
         {
             var startInfo = new ProcessStartInfo
             {
@@ -94,22 +105,8 @@ private static int RunProcessAndWaitForExit(string fileName, string arguments, o
             };
 
             var process = Process.Start(startInfo);
-
-            stdout = null;
-            if (process.WaitForExit((int) TimeSpan.FromSeconds(30).TotalMilliseconds))
-            {
-                stdout = process.StandardOutput.ReadToEnd();
-            }
-            else
-            {
-                process.Kill();
-                
-                // Kill is asynchronous so we should still wait a little
-                //
-                process.WaitForExit((int) TimeSpan.FromSeconds(1).TotalMilliseconds);
-            }
-
-            return process.HasExited ? process.ExitCode : -1;
+            stdout = process.StandardOutput.ReadToEnd();
+            process.WaitForExit();
         }
     }
 }
diff --git a/src/Tasks.UnitTests/Exec_Tests.cs b/src/Tasks.UnitTests/Exec_Tests.cs
index df8ac22edce..3bc0657cab2 100644
--- a/src/Tasks.UnitTests/Exec_Tests.cs
+++ b/src/Tasks.UnitTests/Exec_Tests.cs
@@ -103,8 +103,8 @@ public void ExitCodeCausesFailure()
         [Fact]
         public void Timeout()
         {
-            // On non-Windows the exit code of a killed process is SIGTERM (143)
-            int expectedExitCode = NativeMethodsShared.IsWindows ? -1 : 143;
+            // On non-Windows the exit code of a killed process is SIGKILL (137)
+            int expectedExitCode = NativeMethodsShared.IsWindows ? -1 : 137;
 
             Exec exec = PrepareExec(NativeMethodsShared.IsWindows ? ":foo \n goto foo" : "while true; do sleep 1; done");
             exec.Timeout = 5;
@@ -122,7 +122,6 @@ public void Timeout()
         [Fact]
         public void TimeoutFailsEvenWhenExitCodeIsIgnored()
         {
-
             Exec exec = PrepareExec(NativeMethodsShared.IsWindows ? ":foo \n goto foo" : "while true; do sleep 1; done");
             exec.Timeout = 5;
             exec.IgnoreExitCode = true;
@@ -138,16 +137,13 @@ public void TimeoutFailsEvenWhenExitCodeIsIgnored()
 
             if (NativeMethodsShared.IsMono)
             {
-                // The standard check for SIGTERM fails intermittently on macOS Mono
-                // https://github.com/dotnet/msbuild/issues/5506
-                // To avoid test flakiness, allow 259 even though I can't justify it.
-                exec.ExitCode.ShouldBeOneOf(143, 259);
+                const int STILL_ACTIVE = 259; // When Process.WaitForExit times out.
+                exec.ExitCode.ShouldBeOneOf(137, STILL_ACTIVE);
             }
             else
             {
-                // On non-Windows the exit code of a killed process is generally 128 + SIGTERM = 143
-                // though this isn't 100% guaranteed, see https://unix.stackexchange.com/a/99134
-                exec.ExitCode.ShouldBe(NativeMethodsShared.IsWindows ? -1 : 143);
+                // On non-Windows the exit code of a killed process is 128 + SIGKILL = 137
+                exec.ExitCode.ShouldBe(NativeMethodsShared.IsWindows ? -1 : 137);
             }
         }
 
diff --git a/src/Utilities.UnitTests/ProcessExtensions_Tests.cs b/src/Utilities.UnitTests/ProcessExtensions_Tests.cs
new file mode 100644
index 00000000000..e24dca74ec4
--- /dev/null
+++ b/src/Utilities.UnitTests/ProcessExtensions_Tests.cs
@@ -0,0 +1,30 @@
+// Copyright (c) Microsoft. All rights reserved.
+// Licensed under the MIT license. See LICENSE file in the project root for full license information.
+
+using Shouldly;
+using Xunit;
+
+using Microsoft.Build.Shared;
+using System.Diagnostics;
+using System.Threading.Tasks;
+
+namespace Microsoft.Build.UnitTests
+{
+    public class ProcessExtensions_Tests
+    {
+        [Fact]
+        public async Task KillTree()
+        {
+            Process p = Process.Start("sleep", "600"); // sleep 10m.
+
+            // Verify the process is running.
+            await Task.Delay(500);
+            p.HasExited.ShouldBe(false);
+
+            // Kill the process.
+            p.KillTree(timeout: 5000);
+            p.HasExited.ShouldBe(true);
+            p.ExitCode.ShouldNotBe(0);
+        }
+    }
+}
diff --git a/src/Utilities/Microsoft.Build.Utilities.csproj b/src/Utilities/Microsoft.Build.Utilities.csproj
index 2fdd06afdd6..f42d087cc9f 100644
--- a/src/Utilities/Microsoft.Build.Utilities.csproj
+++ b/src/Utilities/Microsoft.Build.Utilities.csproj
@@ -125,6 +125,9 @@
     <Compile Include="..\Shared\InprocTrackingNativeMethods.cs">
       <Link>Shared\InprocTrackingNativeMethods.cs</Link>
     </Compile>
+    <Compile Include="..\Shared\ProcessExtensions.cs">
+      <Link>Shared\ProcessExtensions.cs</Link>
+    </Compile>
     <Compile Include="..\Shared\ReadOnlyEmptyCollection.cs">
       <Link>Shared\ReadOnlyEmptyCollection.cs</Link>
     </Compile>
diff --git a/src/Utilities/ToolTask.cs b/src/Utilities/ToolTask.cs
index 23f7abc7e67..5ccd30763e2 100644
--- a/src/Utilities/ToolTask.cs
+++ b/src/Utilities/ToolTask.cs
@@ -949,7 +949,6 @@ private void KillToolProcessOnTimeout(Process proc, bool isBeingCancelled)
                         timeout = result;
                     }
                 }
-
                 proc.KillTree(timeout);
             }
         }