Forum:Restarted after a long absence

I haven't played since august. I decided to start playing again with the my same character. I go to existing character, load him up and it says I can't use him because it's from a different user. I had a backup of him on a memory stick. I reloaded it and got the same message. Worse comes to worse I'll start a new guy, I'm just curious if this has happened to anyone else.