Hi Paul,
Hope you are well. Thank you for your quick response. That could be the clue. She was setup as concurrent on the other company and her global user was already setup.
Do users actually need a profile in the other company if they are setup as a Global user? One of things I tried was to delete her account in the other company, she can still access it, presumably as she is a Global user?
I will try the process of deleting and recreating her Global user profile.
Many thanks,
Dil