Fluke is a small iTunes plug-in for Mac OS X 10.6 and earlier version of Mac OS X that lets you play FLAC files at 16bit or 44.1KHz right within iTunes. The Fluke plugin cannot support embedded artwork and will not support playback FLAC files on iPod, iPhone, iPad, Airport Express or Apple TV.
On Mac OS X 10.7 Lion, FLuke is limited to run in 32-bit Mode. To make Fluke run, go into /Applications/iTunes.app/Contents/MacOS/iTunes on your computer, then right-click on iTunes, head to Get Info, and check off “Open in 32-bit Mode”. Some users reported this trick won’t work for them.
Mountain Lion users are not so lucky with Lion users in regards of playing FLAC in iTunes with Fluke as FLuke ceased to update for support of Mountain Lion and no trick works to get Fluke work in iTunes on Mountain Lion.
To play FLAC in iTunes/iTunes 11 on Lion or Mountain Lion, a permanent and simple solution is to convert FLAC to iTunes 11 supported MP3. If you care the audio quality, you can convert FLAC to Apple Lossless or convert FLAC to WAV.
The following includes a step-by-step guide to convert FLAC files to MP3, WAV or Apple Losslesss ALAC to play FLAC in iTunes, iTunes 11 on Lion and Mountain Lion with 4Media Audio Converter