I got my custom GLC last fall loaded with all the options and I've loved it ever since. One feature I get a ton of use out of is the Media Register. Basically you can take your whole iTunes library, and just load the whole thing into the car's storage, and the music is right there. I've had zero problems/glitches with it since I've had the car.

All of a sudden yesterday while I was driving I went to put on a song. I flipped through the COMAND to the Media Register, and it said it was empty/no files were on it. I tried clicking out and going back and it said the same thing. At this point I assumed somehow it deleted everything and I was mad I'd have to reload it all, but puzzled how it happened. Then I turned off the COMAND and turned it back on. Still gone.

When I got to a red light, I shut off the car, opened and closed the driver's door (complete shut off) and then turned it back on. It still said it was empty. I got to my destination, car was off for 30 minutes or so, got back in, songs still gone. I got to my second destination and left the car off about 40 minutes while I was in there. When I came back and started the car again, magically all the songs were back and it worked again. Coincidentally, yesterday it was extremely hot out, the hottest day since I've had the car. I don't know if heat has anything to do with it. I almost burned my hand on the steering wheel when I first got in.

Has anyone else had that problem? What could cause that? Is it a sign of things to come? I had a new Ford Explorer a few years ago and it had similar issues with the garbage "My Ford Touch" system which was an absolute disaster that they got hit with a class action over. The Mercedes system should work better.

 

Almost a year ago to the day I had a bizarre electrical problem with our '17 GLC which played out in a way that may give you some comfort. The car, delivered in October of '16, had been driven from our DC home to Nantucket. About a month into our stay, early one morning, the car was driven about 8 miles into Nantucket town, parked about an hour, then driven a bit in town before the 8 mile return. I parked it at the house for about an hour and then wanted to use it again. When I hit the start button when I got was a cascade of warning messages about various systems being inoperative. Same result on second and third tries.

I left the car for about two hours and then tried again. This time I found the car totally dead electrically. A call to MB assistance yielded an agent who was very confident that the problem was a dead battery (but dead "why") and the dispatch of a truck to give me a jump start.

The jump start worked, as did (per MB's advice) driving the car about an hour to allow the battery to recharge. (The guy who came out for the jump start knew how to access the screen that showed the alternator was working properly.) The next day, and each day thereafter the car has started promptly on request. When checked by my dealer back in DC the battery tested fine, and the only fault codes found indicated impending system failures (though I hadn't gotten--or noticed--any warnings during the drives to and back from town.)

My conclusion is that cars today, especially those with as many "features" as the GLC, are subject to random (or bizarre if you prefer) electrical maladies the cause of which may never be clear beyond the reality of lots of chips, lots of wiring and connections and switches, and at least some lurking software bugs.
I'm not sure all is well, but after a year with no further issue I'm comfortable.

I hope your issue cures itself as well.