diff --git a/cmake/QtBuildRepoHelpers.cmake b/cmake/QtBuildRepoHelpers.cmake
index 16b26545692..fec2445ca5e 100644
--- a/cmake/QtBuildRepoHelpers.cmake
+++ b/cmake/QtBuildRepoHelpers.cmake
@@ -384,7 +384,9 @@ function(qt_internal_qt_configure_end)
     # If Qt is configued via the configure script, remove the marker variable, so that any future
     # reconfigurations that are done by calling cmake directly don't trigger configure specific
     # logic.
-    unset(QT_INTERNAL_CALLED_FROM_CONFIGURE CACHE)
+    if(QT_INTERNAL_CALLED_FROM_CONFIGURE)
+        unset(QT_INTERNAL_CALLED_FROM_CONFIGURE CACHE)
+    endif()
 endfunction()
 
 macro(qt_build_repo)