I recently had to replace my Droid Turbo and was unable to sync the old system calendar with the Google calendar on the new Moto Z Force. I had to get a years worth of appts onto the new calendar for my job. I looked everywhere online without luck. Verizon tech support and Google were unable to help me. I finally downloaded an app from the play store called Copy My Data that pulled all the info to my desktop Google calendar and I was then able to sync. I am posting this in case anyone else has the same issue.