Audacity changed to the new FFMpeg 2.2.2 library. The entry in the audacity.cfg is always reset to "...\\avformat-52.dll" whereas with release of Audacity 2.0.6 the new avformat-55.dll is used. the older one is not recognized anymore.
The entry in launcher.ini (line 56) has to be changed from
Value=%PAL:AppDir:DoubleBackslash%\\FFMpeg\\avformat-52.dll
to
Value=%PAL:AppDir:DoubleBackslash%\\FFMpeg\\avformat-55.dll
This can also be used as workaround until an updated build is released.
This is fixed in 2.0.6 Rev 2. You'll need to manually select it once and then the path will update. Better to remove it than keep up with a silly DLL that changes its filename with every version.
Sometimes, the impossible can become possible, if you're awesome!
FFMPEG lame still not working. where can i find avformat-55.dll file?