Okay, one of the members of the forum has reported that it give this when posting a thread. This just logs them out, how do I remove this?
Go to: AdminCP > Templates > Your theme's Templates > Ungrouped Templates > changeuserbox > and Search the following and remove;
<span class="smalltext">[<strong><a href="member.php?action=logout&logoutkey={$mybb->user['logoutkey']}">{$lang->change_user}</a></strong>]</span>
Okay, thanks I'll try this