iMovie crashes at launch, what to do?

Dear Apple community

I need your help. Imovie keeps crashing when I try to launch it. I'm an experienced iMovie user and this has never happened to me before.

I just updated my system to macOS High Sierra version 10.13.1 and this is the first time I use imovie after the update. I'm working on a project I started in the previous version of iMovie and macOS. It worked fine the first couple of hours, then suddenly it crashed and kept crashing when I tried to restart the program.

I have tried shutting down all other applications and restarting the computer with no success.u help will be greatly appreciated. I have a deadline.