diff --git a/Tests/VSExternalInclude/Lib1/CMakeLists.txt b/Tests/VSExternalInclude/Lib1/CMakeLists.txt
index 1cb01c5dd..9dfac8616 100644
--- a/Tests/VSExternalInclude/Lib1/CMakeLists.txt
+++ b/Tests/VSExternalInclude/Lib1/CMakeLists.txt
@@ -1,3 +1,4 @@
+set(CMAKE_SUPPRESS_REGENERATION 1)
 project(LIB1)
 
 set(SOURCES lib1.cpp)
diff --git a/Tests/VSExternalInclude/Lib2/CMakeLists.txt b/Tests/VSExternalInclude/Lib2/CMakeLists.txt
index f726c3f8b..f4513548d 100644
--- a/Tests/VSExternalInclude/Lib2/CMakeLists.txt
+++ b/Tests/VSExternalInclude/Lib2/CMakeLists.txt
@@ -1,3 +1,4 @@
+set(CMAKE_SUPPRESS_REGENERATION 1)
 project(VSEXTERNAL_LIB2)
 
 include_directories(${VSEXTERNAL_LIB2_SOURCE_DIR}/../Lib1)