By default, Drive for desktop uses the G: Drive letter, so if you had some other server path mapped to the G: Drive, you will need to re-map it to an unused letter.
We do not recommend storing live Thunderbird local mail archives, Outlook .pst files, databases or other highly-transactional files in Google Drive. Instead, these types of files should be stored on your local computer where Druva inSync can back them up if you are concerned about data loss. If you need assistance copying and reconfiguring your Thunderbird archives from local network storage (CIFS) or Google Drive to your local computer and reconfiguring your mail client, then please contact help@lbl.gov