diff --git a/scripts/lib/wic/plugins/source/rootfs.py b/scripts/lib/wic/plugins/source/rootfs.py
index e29f3a4c..977ac0d3 100644
--- a/scripts/lib/wic/plugins/source/rootfs.py
+++ b/scripts/lib/wic/plugins/source/rootfs.py
@@ -54,7 +54,7 @@ class RootfsPlugin(SourcePlugin):
             return os.path.realpath(rootfs_dir)
 
         image_rootfs_dir = get_bitbake_var("IMAGE_ROOTFS", rootfs_dir)
-        if not os.path.isdir(image_rootfs_dir):
+        if image_rootfs_dir == None or not os.path.isdir(image_rootfs_dir):
             raise WicError("No valid artifact IMAGE_ROOTFS from image "
                            "named %s has been found at %s, exiting." %
                            (rootfs_dir, image_rootfs_dir))