diff --git a/appveyor.yml b/appveyor.yml
index 225515c0..fecc5fed 100644
--- a/appveyor.yml
+++ b/appveyor.yml
@@ -2,7 +2,7 @@ version: 1.0.{build}
 environment:
   matrix:
   - COMPILER: "gcc"
-    MAKE_PARAMS: '"make -C tests zstd fullbench fuzzer paramgrill datagen CC=clang MOREFLAGS="--target=x86_64-w64-mingw32 -Werror -Wconversion -Wno-sign-conversion"'
+    MAKE_PARAMS: '"make -C tests zstd fullbench fuzzer paramgrill datagen CC=clang MOREFLAGS="--target=x86_64-w64-mingw32 -Werror -Wconversion -Wno-sign-conversion""'
     PLATFORM: "clang"
   - COMPILER: "gcc"
     MAKE_PARAMS: '"make test && make lib && make -C tests test-symbols fullbench-dll fullbench-lib"'