Hi, I'm new to Ubuntu & have the error as stated in the title of this thread.
I'm not sure why or how this could have happened as my laptop was working fine earlier in the day with no boot problems. I switched on to use Sat pm & the error message appeared?!?
I have been reading the solutions in the Ubuntu documentation and have tried to resolve, the 'Set' command brings back the following:
but the 'Is' command coming back as an 'Unknown command'.
So I'm not stuck with how to get my system up & running again.