diff --git a/CMakeLists.txt b/CMakeLists.txt
index 77e170bfb55a8a8398b127ab300665a659c00453..d8b5bd96abea7a7d4acb357ec130894780dc4700 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -1257,7 +1257,8 @@ set(CPACK_SOURCE_IGNORE_FILES "${CMAKE_CURRENT_BINARY_DIR}" "/CVS/" "/.svn" "~$"
     "DS_Store$" "GmshConfig.h$" "GmshVersion.h$" "/benchmarks/" "/tmp/" 
     "/bin/" "/lib/" "/nightly/" "GPATH" "GRTAGS" "GSYMS" "GTAGS" "/HTML/" 
     "/projects/" 
-    "/FunctionSpace/" "/Mesh/meshRecombine*" "/utils/solvers/legacy/")
+    "/FunctionSpace/" "/Mesh/meshRecombine*" "/utils/solvers/legacy/"
+    "/contrib/3M/")
 
 if(UNIX)
   # make sure we remove previous installs before doing the next one