[Mr Marcus]

I had my windows professionally tinted (not by BMW) and after driving 200 yds after collecting it flashed up a message saying "complete electrical failure it is no longer safe to complete your journey".

Turns out window tinters use a lot of liquid to clean the windows and despite their efforts to mop it all up some got down the back window and under the parcel shelf. It ran down the wiring looms and into the control unit under the boot completely buggering it up, luckily for me though their insurance company paid for it all to be replaced.