InDesign won't open on my MacBook Pro (Mac OS X 11.3.1)

I can no longer open InDesign files on my nearly new MacBook Pro.

It's a progressive problem, first noticed a week or two ago. At first it could usually be resolved by quitting and restarting INDD. More recently I've had to restart the computer. Now I've restarted and STILL can't open InDesign. It's now a major problem as I have to get work out tonight. I'm about to try rebooting in Safe mode but even if that works it's not a satisfactory solution.

Anybody seen this before? And, if so, how did you resolve it?

Thanks.