--- a/mercurial/extensions.py
+++ b/mercurial/extensions.py
@@ -70,6 +70,8 @@ def loadall(ui):
result = ui.configitems("extensions")
for i, (name, path) in enumerate(result):
if path:
+ if path[0] == '!':
+ continue
path = os.path.expanduser(path)
try:
load(ui, name, path)