diff --git a/dom/file/File.cpp b/dom/file/File.cpp
index 68403a758a5f2..60c3e7d244d74 100644
--- a/dom/file/File.cpp
+++ b/dom/file/File.cpp
@@ -135,11 +135,7 @@ already_AddRefed<File> File::Constructor(const GlobalObject& aGlobal,
                                          const nsAString& aName,
                                          const FilePropertyBag& aBag,
                                          ErrorResult& aRv) {
-  // Normalizing the filename
-  nsString name(aName);
-  name.ReplaceChar('/', ':');
-
-  RefPtr<MultipartBlobImpl> impl = new MultipartBlobImpl(name);
+  RefPtr<MultipartBlobImpl> impl = new MultipartBlobImpl(aName);
 
   nsCOMPtr<nsIGlobalObject> global = do_QueryInterface(aGlobal.GetAsSupports());
   MOZ_ASSERT(global);