My Garmin 910XT is frozen in "transferring data" mode. Won't turn off, won't shift modes.
There's a 35 minute wait at the call-in help line. And the email-a-concern line isn't functioning.
You can try also this. Not sure whether it helps, but trying it won't harm anything:
My Garmin forerunner was locked on the 'transferring data' screen and this worked for me without losing any data:
For the 910XT you might need to try a master reset. It's a little tricky and requires some dexterity. Good instructional video here:
Glad you got it working.
Apologies to Garmin for delaying a new device purchase. 