Thread:Project:Support desk/How to Remove Access/reply (3)

First you should take the user out of the special user groups, he might still be in, see Help:Assigning_permissions for that. Additionally you can then block the user as described at Help:Blocking_users. The user will then only be able to log in, but he won't be able to do anything else; for him the wiki is read-only then. If you even want to prevent him from logging in, then you can additionally change his username, e.g. with Extension:Renameuser.

Ahh: And you can delete the user's userpage (just in case you want to be really clean).