diff --git a/easybuild/base/generaloption.py b/easybuild/base/generaloption.py
index 13bd3b80c7..51f7daafe3 100644
--- a/easybuild/base/generaloption.py
+++ b/easybuild/base/generaloption.py
@@ -1149,7 +1149,8 @@ def add_group_parser(self, opt_dict, description, prefix=None, otherdefaults=Non
                 if len(str(default)) == 0:
                     extra_help.append("default: ''")  # empty string
                 elif typ in ExtOption.TYPE_STRLIST:
-                    extra_help.append("default: %s" % sep.join(default))
+                    if default:
+                        extra_help.append("default: %s" % sep.join(default))
                 else:
                     extra_help.append("default: %s" % default)