I'm running On Premise TFS 2018 Update2, and i'm trying to migrate to TFS online. I'm at the point where i need to make a dacpac of my collection, and in order to do that i need to detach my collection like they outline here:
https://docs.microsoft.com/en-us/tfs/server/admin/move-project-collection?view=vsts#detach-coll
when i try to detach however, i get the error in the title. Any ideas how to get past this? The only thing i've found similar to this issue is at:
https://social.msdn.microsoft.com/Forums/vstudio/en-US/e6ad3a1a-bfe0-44a9-a3e6-3442004c7687/tf400856-error-identity-management-is-not-registered-in-the-database?forum=tfsadmin
which basically says 'uinstall TFS and reinstall it back from backup', which i'd really rather not try if there is an easier way.