Hey,
Sorry to hear about your issue with the game crashing.
First of all, I would suggest to try the steps found
here but for issues like this we really need to be able to look at your system files to help see what may be causing it.
Another good thing to try is to close Uplay, go to your cache folder in your Uplay directory and rename your cache folder to something like "cachebackup". Then see if you still have an issue.
If you have done those steps, I would recommend trying to get through on live chat during times that we are open so we can get your system files off you.
We have times listed on
here when you should be able to get through. I apologise it's not the most convenient way for everyone to send us the system files at the moment, but due to limited support during the current times, only live chat is available to get a support ticket created.