Judge a smidge of background first. I came in this morning and the Hyper-V guest of our windows server domain controller was getting paused while booting with a disk IO error of some sort inside the VM (there were no error within the cluster itself). It turned out that due to an issue I’m having with the DPM backups that I had a half dozen snapshots stacked up for the server. After merging them all the server then stopped getting paused but then did bluescreen with the error 0xc00002e2 and the Internet was less than helpful.

The error is caused by an issue with the active directory database and running a repair on it helpfully fixed it up. I first booted to the repair mode command prompt and tried to run esentutl /p against ntds.dit, but it failed with the error “Unable to find the callback library ntdsai.dll” and the fix for that was to run the utility from the Windows instance that was being repaired. In this case the repair tool dropped me off to an X:\ drive, but the Windows instance that I wanted to repair was actually the E: drive. So I changed the path to e:\windows\system32 so the command was something like:

cd e:\windows\system32
esentutl /p e:\windows\ntds\ntds.dit

I honestly figured it would fail, but it ran through successfully and the server booted up fine afterwards. Note that I have other DCs for this domain so I didn’t have to worry too-too much about the actual data and state of the DS database since it was just going to plowed over with the objects from one of the other DCs.