OpenCart Community

Hi,
I am having the same problem as viewtopic.php?f=199&t=225546 and by following the steps provided above, the issue can indeed be fixed.
To avoid this problem to happen again, I tried to find the root cause without much success, thus I would like to know if somebody would know ?

Could be caused by a buggy extension trying to write to the oc_user_group table or add permissions. Another cause could be some sort or error when editing the user group permissions.