diff --git a/src/Nerdbank.GitVersioning.Tasks/ContextAwareTask.cs b/src/Nerdbank.GitVersioning.Tasks/ContextAwareTask.cs
index f3bb3e17..7ba03cb6 100644
--- a/src/Nerdbank.GitVersioning.Tasks/ContextAwareTask.cs
+++ b/src/Nerdbank.GitVersioning.Tasks/ContextAwareTask.cs
@@ -56,7 +56,7 @@ public override bool Execute()
             // On .NET Framework (on Windows), we find native binaries by adding them to our PATH.
             if (this.UnmanagedDllDirectory is not null)
             {
-                string pathEnvVar = Environment.GetEnvironmentVariable("PATH");
+                string pathEnvVar = Environment.GetEnvironmentVariable("PATH") ?? string.Empty;
                 string[] searchPaths = pathEnvVar.Split(Path.PathSeparator);
                 if (!searchPaths.Contains(this.UnmanagedDllDirectory, StringComparer.OrdinalIgnoreCase))
                 {