diff --git a/CMakeLists.txt b/CMakeLists.txt
index 9f6040e1a..770ffd2b5 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -104,7 +104,6 @@ if(MSVC)
     add_compile_options(/utf-8)
     add_compile_options(/permissive-)
     add_compile_options(/Zc:lambda)
-    add_compile_options(/FI${PROJECT_SOURCE_DIR}/src/permissiveworkarounds.h)
 
     # Workaround C1128 error
     add_compile_options(/bigobj)
diff --git a/src/permissiveworkarounds.h b/src/permissiveworkarounds.h
deleted file mode 100644
index c14fc65cc..000000000
--- a/src/permissiveworkarounds.h
+++ /dev/null
@@ -1,8 +0,0 @@
-// SPDX-FileCopyrightText: Copyright (C) 2018 swift Project Community / Contributors
-// SPDX-License-Identifier: GPL-3.0-or-later OR LicenseRef-swift-pilot-client-1
-
-//! \file
-
-// Workaround for "unexpected token 'identifier'" in combaseapi.h when compiling with /permissive-
-// https://developercommunity.visualstudio.com/solutions/187139/view.html
-struct IUnknown;