TF10158 error when trying to perform "Convert to branch" on a folder using Eclipse

[chapmasc]

Full error looks like:

TF10158: The user or group name LastName, FirstName contains unsupported characters, is empty, or too long.

Background. I believe this is caused due to our Domain, there is a test domain and a prod domain. The user is the same between the two though. I know I receive a ambiguous error if I use a command line command and do not provide the domain\userID, and instead use the Friendly Name "LastName, FirstName".