"Checking System........" forever

Hey @rob11521, Welcome to the community!

Can you please provide your local-by-flywheel.log file? See this Community Forum post:
How do I retrieve Local’s log file? for instructions on how to do so.

Since Local isn’t opening you can find the logs at ~/Library/Logs/local-by-flywheel.log

There might be more information about what Local is having issues within there!