diff --git a/.github/workflows/cmake.yml b/.github/workflows/cmake.yml
index 4b1653064..6098f30b5 100644
--- a/.github/workflows/cmake.yml
+++ b/.github/workflows/cmake.yml
@@ -188,7 +188,7 @@ jobs:
               -DBUILD_SHARED_LIBS=OFF
               -DCMAKE_CXX_COMPILER=clang-cl
               -DCMAKE_C_COMPILER=clang-cl
-              -DCMAKE_CXX_FLAGS="/source-charset:utf-8 /DUNICODE /D_UNICODE"
+              -DCMAKE_CXX_FLAGS="/utf-8 /DUNICODE /D_UNICODE"
             testargs: >
               -GNinja
               -DCMAKE_BUILD_TYPE=Release