Got in this morning to find that users permissions on their user areas have disapeared.

Their username is still in the permission list but none of the boxes under Allow/Deny are ticked, it's not global either as about 3% of users in each OU are unaffected, none of the inherited permissions are affected either and only 3 out of 5 of the year groups.

Very weird, I have now ticked all the full control boxes for all the students by hand, ouch!

Anyone else experienced thison Server 2008 R2?