This is just a short blog article on a problem I experienced when upgrading Azure AD Connect from a previous version. This was a small environment where the Azure AD Connect server was running on the Domain Controller.
When starting the upgrade process I noticed that a message was displayed that a “Group with name ADSyncAdmins was not found in the Machine context”. When I clicked to Upgrade anyway, an error message was displayed that it was “Unable to upgrade the Synchronization Service”:
Looking into the event log, I found this error:
Product: Microsoft Azure AD Connect synchronization services — Error 25037.The groups entered do not all exist or cannot be found. Verify that each group name is correct, and then try again.
Since this was a Domain Controller, and there is no Local Users and Groups, I created the ADSyncAdmins group in Active Directory, as a Domain Local Security group. Trying the upgrade again, I got a new group that was missing:
So I ended up creating these 4 groups that was missing:
After that I was able to successfully finish the upgrade of Azure AD Connect.