Errors adding new user to switch 1

[matt]

After detaching my user from my switch to set up switch 2, someone else in my family has taken over my switch 1.

However when they add a new user the screen comes up with S0025 (21558028) error code after hanging on preparing screen .

Does anyone know what the problem could be? Stupidly I didn't ask her to reset to factory and now she's made a nice island.

Go to Settings > User > Add User, just hangs / times out on preparing and then comes up with the above code.

Thanks