CAD freezes or locks when you open, save, or Xref drawing files that are stored in a shared online folder using a service such as Google Drive or Dropbox.
This issue is likely the result of a caching/syncing issue between CAD and your shared online service.
1. With CAD closed, set any folder(s) containing DWGs and files being worked on to be available online only.
Your shared online service will need to sync with the folders you've set to be available online only. Wait for that sync to finish.
2. After the sync has completed, set the folder(s) back to local or available for offline use so they're stored on your computer.
Wait for this sync to finish, then reopen CAD. Repeat the action that caused CAD to freeze or lock. If it functions correctly, you've resolved the issue.
Instructions and terminology for storing folders and files online vs. local will vary depending on which shared online service you're using. Check with your vendor for this information.