https://bugs.winehq.org/show_bug.cgi?id=47894
--- Comment #2 from Sven sven.wine@gmail.com --- I'm not sure about the actual error dialog, since I don't have a Windows installation to test it on, but you can find an error dialog in the logs with the title "mfreadwrite_test.exe - Unable To Locate Component". In the logs on Windows XP, there is a similar dialog for mfplat, but that one doesn't seem to cause the failure (even tough there are other failures):
https://test.winehq.org/data/7d954f23356f0aaf49b1ef0c4bed83041cb41c08/xp_fg-...
I'm not sure how winetest is supposed to handle missing libraries, but I found it weird that the test only fails if the error dialog is present.
It could also be that the winstation tests should just be fixed, since the test also fails sporadically on Windows 7, but without the mfreadwrite error dialog being present:
https://test.winehq.org/data/363b8809f37b3ea5915ea4240b3d397fd2355e2e/win7_f...