Last week I was removing a really old Window Server 2008 domain controller. As part of that process I needed to remove the Active Directory Certificate Services role.
It took an absolute age and looked like nothing was happening for a while.
Eventually I got an error code “0x80073701. The referenced assembly could not be found”
After a very quick google I found some details about it being a problem with adding and removing services itself as opposed to it specifically being an AD Certificates Services issue.
So I thought I’d test that by adding another role (print server)
Yep, same issue
So I had a quick look through the event log and saw tons of events related to making a change to the status of installed updates (didn’t screenshot them or note exactly what the message was unfortunately!)
Next step was to take a look at the CBS logs
CBS.log and CBS.persist.log
In there was the error “ERROR_SXS_ASSEMBLY_MISSING” as well a specific update.
So I uninstalled it and rebooted.
I probably could have re-installed the update but as the whole point in this case was to decommission the server I didn’t see much point.
After the server came back up I tried to add the print server role again and got exactly the same error. I checked the CBS logs again and found the same missing assembly error but with a different update. So I removed that one, rebooted again and I was then able to add the print server role without issue.
With that sorted I then tried to remove the certificate services role and this time around it was successful.
The short version, for when I come back here as it’s happened again
- Check the CBS logs for ERROR_SXS_ASSEMBLY_MISSING
- Remove or reinstall the update mentioned and reboot
- Attempt the role change again, repeat until it works!