I just started at a company who've been using cloned VMs and only changing the server names. They didn't run sysprep or newsid. Lately one of our VMs has been losing domain connectivity and we realized the AD object is disappearing. Question 1: Is this because of a duplicate SID? Question 2: Can we run Newsid (I know it's not supported) or Sysprep on this machine, keep the server name the same and that should be fine? Question 3: If question 2 is no, how do we change the SIDs without messing up our applications (SQL Server, etc)? Thanks!

Question 1: Is this because of a duplicate SID?Most Likely. There is not enough information to make a 100% determination. However, I can tell you for a fact that even though computers with identical SIDs generally function within a domain, there are many applications that will not work properly because of this issue, such as SMS/SCCM. Question 2: Can we run Newsid (I know it's not supported) or Sysprep on this machine, keep the server name the same and that should be fine?Yes, you definately use one of those tools to generate a new SID. I have used both successfully. There should be no impact to any applications running on the local machine.Note: If you do run SYSPREP, please refer to this link as there is important information that you should now about when running SYSPREP more than 3 times on a computer.http://technet.microsoft.com/en-us/library/cc766514(WS.10).aspx Visit my blog: anITKB.com, an IT Knowledge Base.

Thanks. I guess we'll need to take it off the domain, run sysprep or newsid (but keep the name the same). Put it back on the domain (so new AD object is created). And you think as long as the IP address and server name stay the same the applications should still be fine? that's good news because everyone around here is concerned about this.