diff --git a/CMakeLists.txt b/CMakeLists.txt
index 4cca59ccceafa53cb64b475945c97f1a960ebbaa..06a273e2cf89ec695b7c81edf91fdd8e5a02a270 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -843,7 +843,7 @@ if (MPI_FOUND)
 else()
   if (PUGS_ENABLE_MPI MATCHES "^OFF$")
     message(" MPI: explicitly deactivated!")
-  elseif((NOT PUGS_HAS_PARMETIS) and (NOT PUGS_HAS_PTSCOTCH))
+  elseif((NOT DEFINED PUGS_HAS_PARMETIS) and (NOT DEFINED PUGS_HAS_PTSCOTCH))
     message(" MPI: deactivated: ParMETIS and PTScotch cannot be found!")
   else()
     if (PUGS_ENABLE_MPI MATCHES "^(AUTO|ON)$")