We have a problem that happened last week. Where for what ever reason we had some user accounts and a group disappear from our Active Directory. No one was logged in as an admin and no changes were made that day. This prevented the users from logging into the AD. Later in the afternoon the accounts and group reappeared and no one again was logged in as admin to make any changes. Has anyone seen this problem or have any idea what to do to prevent it from happening again?