Pass window fault

[Brad.]

Looking for ideas, was at my mates garage earlier (cars still there) I went to wind the window Down, came half way and went 'click' quite loud, as if the glass had come off what holds it to the motor/regulator

I'm getting it back tomorrow or Monday but looking for some ideas on common issues? Il be faking door card off etc anyway but all ideas help to find the fault.

Many thanks.