This has happened a handful of times, reason yet to be discovered, but usually when it is raining. I put the power windows up and lock the car with the key fob. I return a couple hours later to find the windows have lowered themselves to about three inches on either side. Dealer and 866 ASK MINI have not encountered this problem. Has anyone else? Only other problem I have had is opening rear hatch with key fob. Need to use manual open and close or will not catch.

 

The only time my windows have come back down on me are immediately after putting them up, because the system has gotten out of whack with the positioning of the window. Is it both windows? Maybe your dealer can just reprogram them and see if it continues to happen.

 

If you search for "windows rolling down by themselves" or some other target words meaning the same, you will find that you are not alone. This happened to many people during rain storms. I am surprised that MINI is still giving answers that suggest that they know nothing of the problem.