diff --git a/CMakeLists.txt b/CMakeLists.txt
index 818a3da..e8b3bed 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -19,3 +19,3 @@ IF (WIN32 AND MSVC)
   set (CMAKE_CXX_FLAGS " -DNDEBUG")
-  add_compile_options("/O2" "/W4" "/GS" "/Gy" "/guard:cf" "/Gm-" "/Zc:inline" "/fp:precise" "/GF" "/EHsc" "/ZH:SHA_256")
+  add_compile_options("/W4" "/GS" "/Gy" "/guard:cf" "/Gm-" "/Zc:inline" "/fp:precise" "/GF" "/EHsc" "/ZH:SHA_256")
   add_compile_options("$<$<CONFIG:Debug>:/Od>")