Sage restore problems

I was looking to restore a clients data  files  for Sage to my own version of Sage.

Original back up was fine & sage goes through restore process ok e.g you can see the files being restored as normal.

However at end of process Sage prompts for username & password.

On entering correct username & password error message appears re incorrect username/password. I have checked username & password and both are correct.

Never had this problem before.

Any suggestions?