We were working on migrating our Domain Controllers from Windows 2008 R2 to Windows 2019 and I got to the point where I was running the PowerShell “Test-ADDSDomainControllerInstallation -DomainName MyDomain.Name” command to test migration requirements. The process was kicking out an error for part of it with a context of Test.VerifyDcPromoCore.DCPromo.General.103 so I started the hunt for what that meant. Well both the Bings and Googs came back with no results at all for the exact search value. Plenty of other items with different numbers at the end but not specifically 103.
You can see the exact output from the image below.
I finally found a hint in the Event Viewer -> Applications and Services Logs -> DFS Replication with a DFS Replication erro 6104. “The DFS Replication service failed to register the WMI providers.” This jogged my memory that these were originally Windows 2003 Domain Controllers that were migrated to Windows 2008 R2 which meant they were still using FRS Replication for their SYSVOL data. I went looking and found Windows 2016 RS3 and Windows 2019 completely removed FRS support. This meant I needed to first migrate our systems from using FRS to DFSR before I could move forward with adding the Windows 2019 servers as Domain Controllers. I used the two MS guides below to work through this process which on our small domain took 1-2 hours to complete with testing.
Quick Guide – https://techcommunity.microsoft.com/t5/Storage-at-Microsoft/Streamlined-Migration-of-FRS-to-DFSR-SYSVOL/ba-p/425405
Excessively Long Guide – https://docs.microsoft.com/en-us/previous-versions/windows/it-pro/windows-server-2008-R2-and-2008/dd640019(v=ws.10)
Once that was completed I was able to run the PowerShell test command again and everything succeeded. So Test.VerifyDcPromoCore.DCPromo.General.103 is code for “upgrade your old junky FRS SYSVOL to DFSR” obviously!