diff --git a/scripts/lib/CIME/utils.py b/scripts/lib/CIME/utils.py
index d4c847c628e..a3f7da17dda 100644
--- a/scripts/lib/CIME/utils.py
+++ b/scripts/lib/CIME/utils.py
@@ -45,7 +45,7 @@ def check_name(fullname, additional_chars=None, fullpath=False):
     True
     """
 
-    chars = '<>/{}[\]~`@' # pylint: disable=anomalous-backslash-in-string
+    chars = '<>/{}[\]~`@:' # pylint: disable=anomalous-backslash-in-string
     if additional_chars is not None:
         chars += additional_chars
     if fullpath: