That sounds like something went very wrong (or the update didn't complete). Which desktop environment?
Since the Files doesn't work, if you're on GNOME or Budgie, can you try running nautilus
from the terminal and see what error comes up?
By the way, I would also recommend sudo eopkg up
from the terminal to make sure you really are up-to-date. If that is the case, then maybe a restart would be in order.