Membership to multiple usergroups and conflicting permissions
 

I've read the part in the manual about that, but I still don't get it.

A user is a member of 2 usergroups.
The primary allows him to post in a specific forum using forum permissions.
The additional does not allow him to post in the same forum.
The access masks for that users are set to default.

The manual states that YES always overrides NO. Why is it then he can't post in the forum?

Thank you.

Yes overrides No and a smaller number of permissions will override the lesser. Does he have more YES permissions in his Primary Usergroup?

If any of his usergroups has permission to post in the forum, then he should be able to. But make sure you have ticked can have membergroups for his primairy usergroup.

Another problem: a single user is a member of a newly created usergroup (his primary and only usergroup). The idea of the usergroup is to sent his posts to moderation queue, which is applied to a number of forums only (this is set with forum permissions).
The problem is: he gets no permission everywhere on the board
I've checked his usergroup permissions (can view forum is YES), forum permissions (can view forum is YES) and access masks (all is default) and all seems fine.

Is it a problem that he is not a member of his previous primary group Registered Users?
It is beyond me what causes the problem. Please help.

Anyone please. I can't think of any resolution to the problem above. And it looks so stupid.

I don't know if that is related, but when the user is in the troubled usergroup (no access at all) he gets an error on top of the page:

Anyone?

I would double check the permissions, because if his usergroup allows access he should be able to browse the forums.

The error message is most likely from a modification.

To troubleshoot this, please remove any hacks and disable your plugins, then see if you still have this problem.
Note: To temporarily disable the plugin system, edit config.php and add this line right under <?php

define('DISABLE_HOOKS', true);

If so, reupload all the original vB non-image files (except install.php). Make sure you upload these in ASCII format and overwrite the ones on the server.

Its not from a modification i have had this problem on one of my boards before. I'd try ask over at vb.com