https://bugs.winehq.org/show_bug.cgi?id=38421
--- Comment #5 from Nikolay Sivov bunglehead@gmail.com --- Yes, I can confirm that it's related to this patch. So far I can see that making DMOGetName() return a code on failure that passes SUCCEEDED() check makes it work properly again. However it's not a right thing to, as my patch shows https://www.winehq.org/pipermail/wine-patches/2015-April/138796.html - we should really return E_FAIL in this case.
What wmp does doesn't make much sense - it tries DMOGetName for every guid in HKLM\Software\Microsoft\MediaPlayer\NodeCLSIDs. I checked on windows and DMOGetName fails on such guids as expected.
So it looks like this change uncovered some other problem, which is good in general.