We're so sorry to hear about the trouble. We will try our best to help you with this. I'd request if you can share a few more details like:
A screenshot of the About XD info page and the version of the Operating System.
Please share more details about the challenges you face while sharing the files? If there any specific error that you get?
While collaborating with other Team members, please ensure that all the users have the same latest version of XD and if XD is up to date, could you confirm if you are getting any error code or message while inviting?
When exactly the software crash? Is there any pattern?
Are you connected to a private network or an enterprise network?