Hi all, long time reader but I registered because of this issue! Since update to 11, iTunes behaves abnormally: stops randomly during mp3 or any audio playback, random wait, continue playing. System: Model Name: mac pro Model Identifier: MacPro5,1 Processor Name: 6-Core Intel Xeon Processor Speed: 3.33 GHz Number of Processors: 1 Total Number of Cores: 6 L2 Cache (per Core): 256 KB L3 Cache: 12 MB Memory: 24 GB Processor Interconnect Speed: 6.4 GT/s Boot ROM Version: MP51.007F.B03 SMC Version (system): 1.39f11 SMC Version (processor tray): 1.39f11 Serial Number (system): xxxx Serial Number (processor tray): xxx Hardware UUID: xxxx OS X 10.8.2 (12C60) Darwin 12.2.0 SSD boot drive iTuines Library is on a software RAID 0 from 4 2TB WD Black Caviars, supervised by Drive Genius. They have their bad blocks but nothing spectacular. The FUNNY THINGS: iTunes Library didn't change, was working flawlessly up till a month ago, on the same system. I decided to revert back to iTunes 10 - had a CCC boot drive copy from early 2012. Reset to Lion - update to 10.8 , old iTunes CONTINUED RANDOM STUTTER. I was shocked. Deleted iTunes with the APP Cleaner. Clean re-install iTunes 11, updated system to latest standard - still stutter. Shocked again. Changed Library, reimported all songs, Sharing OFF, Crossfade OFF, all iOS devices offloaded, iTunes bare feet... still stutters! OBSERVATIONS: If I am working on the MAC, it seems to be OK. Left for >15 min - Stutters: SLEEP function interference??? Sleep OFF, Hybernation OFF, Hard Disks never sleep etc etc, restarted, iTunes still stutters. I am speechless!!! 250 GB best Apple lossless classical music library, optical TOS-Link to a nice HiFi, lossless to 5 Heil AMT speakers... This issue kills me! Please help if someone knows what! Thanks++ ---------- One poster somewhere mentioned interference with second monitor. I unplugged my second NEC PA. Restarted and ... iTunes still stops playback randomly, to continue randomly seconds later. OK, now over to you. OK, after 3 hours of testing - it is true that iTunes doesn't stutter if I work on the computer, i.e. constant activity. But starts when I leave it playing alone. haven't tried with video files yet.