we had a situation today where ALL of the members out of ALL our SharePoint groups were removed. We confirmed through the audit log report that no user was responsible for this, so it must have been a system issue. Apart from that, this seems to have happened within a space of about 15 minutes, and its very difficult to wreak this kind of havoc in this short space of time.
Has anybody heard of anything like this before? What would possibly cause something like this?