DVD writer suddenly stops working - not recognized on ThinkPad - Windows 7

How To


DVD writer suddenly not recognized on my Lenovo ThinkPad T420i and the device manager shows device but flags it as problem driver with a (!) bang.

I'm running Windows 7, 64 bit and when I do a system restore to earlier time when drive worked, it appears and after updates to machine (windows updates) it disappears again - can I not lock the driver when I get it to work?


This symptom has been reported on other ThinkPads running  Windows 7 -  driver "missing or corrupted" and whenever  "Update Driver" selected, the system indicates that the driver was already up-to-date.


The issue seems to relate to Windows registry keys that refer to UpperFilters and LowerFilters.

This symptom may be caused by iTunes inserting a hidden software "filter" between Win7 and i'ts device driver.   A bad (eg, corrupted or missing) filter prevents Windows from talking to its device driver.   So removing a filter from the registry tells Windows to talk directly to the driver.


Using "regedit", follow these MicroSoft instructions to delete both the "UpperFilters" and "LowerFilters" registry keys.  This should restore DVD operation.