Sorry to hear about the trouble. Please share a few more details like:
A screenshot of the About XD info page.
The version of the Operating System.
While using XD, please take a screenshot of the Task Manager/Activity Monitor capturing the memory utilization of XD.
Regarding other issues like "Error occurred when file open in new version and second user working on other version of the file", it's necessary for all the collaborators to be on the latest version of XD.