Not sure if you are having the same problem as me. I was getting random crashes and eventually noticed trouble saving data. I was having to hook my 908 up to my laptop and run chkdsk to fix disk errors. Note I'm running windows 10 and used chkdsk from command prompt and it takes awhile to run. Then eventually one of the last updates I got before my subscription expired added a built in file checker.
If you hit the home icon at the bottom left, and have a Maxitools icon in the list you can use that to scan for disc errors. I've noticed since they added that my system will pop up a warning on startup sometimes telling me I have errors. I still occasionally get random crashes and when it happens I run the checker and it almost always finds bad spots.
I've been hesitant to try to deal with Autel directly. I've had my unit since Feb 2014, I'm the only one who uses it and I still get good battery life and my screens in great condition. Don't want to send it off to get fixed and find out I'm worse off with a replacement/refurb unit.
I've only paid for one update and that's now expired. Keep going back and forth about updating or waiting for this one to fail and replacing it with a newer model. The tool is far from perfect but it is amazing what it does for the price.