Got this from the link below it. Found it when I was looking for my door striker problem. Some people try changing the switch first but... I don't think that works... I've seen another write-up somewhere else as well but I can't seem to find it.
Anyhow check the link at the bottom. If you go through it thoroughly there are a number of possible solutions.
"famous window problem:
many people have window problems with e36 when their windows roll up or down by half an inch at one time.
the window motor has motion sensor inside which takes info from magnetic ring that is on motor shaft. for some reason this ring dislocates and sensor gets no info so motor drive circuit thinks its stuck.
all you have to do is to open motor and relocate this ring. on sedan it can be done without taking window mechanism apart ( and drill rivets) on coupe you have to take mechanism on table.
magnet ring is marked red and red arrow points toward its place where its have to be" http://forums.bimmerforums.com/forum...d.php?t=238468