It probably means your regulator is going bad. If you take off the door panel you may be able to see that one or more teeth on the regulator are missing or ground down. The solution is a new regulator which is maybe $100 and a couple of hours of DIY labor, although it can be a frustrating couple of hours.

One of the screws holding the regulator to the door sheet metal serves as an "adjustment." When you install a regulator/motor assembly, using this screw you can adjust between won't work and works smoothly. I'd propose "out of adjustment" is more likely than "broken tooth."

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Kent Christensen
Albuquerque
'07 GL320CDI, '10 CL550. '01 Porsche Boxster
Two BMW motorcycles

Sounds like all the bolts on the regulator are loose.

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