Hey @benselby - thanks for being a long-time Local user!
Do you know if your Mac is an Intel Mac or Apple Silicon (M1/M2)?
We were troubleshooting this with another user in a different thread - can you try closing Local, deleting this folder:
Mac: ~/Library/Application Support/Local/lightning-services
and then relaunching Local? We’re working on a fix right now, but that is a workaround that should resolve your issue.
No need to worry, your sites are fine and not going anywhere!