diff --git a/CMakeLists.txt b/CMakeLists.txt
index 085d00e0b..431901fba 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -226,6 +226,8 @@ else(USE_SYSTEM_SINGLEAPPLICATION)
   set(SINGLEAPPLICATION_INCLUDE_DIRS ${CMAKE_CURRENT_SOURCE_DIR}/3rdparty/singleapplication)
   set(SINGLEAPPLICATION_LIBRARIES singleapplication)
   set(SINGLECOREAPPLICATION_LIBRARIES singlecoreapplication)
+  unset(SINGLEAPPLICATION_LIBRARY_DIRS)
+  unset(SINGLECOREAPPLICATION_LIBRARY_DIRS)
 endif(USE_SYSTEM_SINGLEAPPLICATION)
 
 # Qocoa