We don’t ship our equipment with a Windows password set. We only ship them with a default Windows account username “Tek_local_admin”.
It’s likely someone may have changed it and didn’t notify others. I know some of our rental partner use ‘oem’ as a password on their rental units if that’s its origin.
I’ve also seen reference to a BIOS password ‘Tektronix’ on some of our scopes, but that’s about it.
If the password remains unknown, the only way to recover the AWG is though an operating system restore procedure.