The specified account already exists

Tried the usual clean install /run as administrator after uninstalling 14.3 /cleaning registry etc, but 15 refuses to install saying 'The specified account already exists'. After a bit of head scratching, I logged out & back in again via an administrator account. This time 15 installed. Re-booted into my user account and all seems to work.
Still, haven't seen this particular issue before.
Still, haven't seen this particular issue before.