In iTunes how do you turn off "Determining Gapless Playback Information"

"Afaik, Apple does not provide an option to turn this off in iTunes. Try the method suggested in the 2nd page of this post: iTunes - Determining Gapless Playback Information.

You may also have to turn on the Crossfade option for the above workaround to have an impact: Apple Support:What is Gapless Playback?"

"Ok. I have 15,000 plus songs, samples, sound effects, and various things I use Itunes for. This came a problem my first upgrade. I keep all files on an external hard drive to not bog down my computer. I recently upgraded to windows 7 from vista and had to restart the gapless playback problem?

find the folder where all you music is located such as c/justin/mymusic and rename it
to anything new c/justin/mymusic2
Turn on itunes. It should not do too much. It should have no songs to start going insane and freeze.
Go to edit select all and right click all your highlighted songs to get info. It will ask if you really want to edit all the files at once, yes you do, go to the far right tab ""options"" go to the bottom and select gapless playback and toggle it to say yes.
find the original folder you changed to c/justin/mymusic2 and change back to c/justin/mymusic
Go to edit-preferences-advanced-make sure it is getting songs from original music file click ok. It should now just take some time to load up itunes library. No Gapless Playback Lag!
The crossfade option can also be used which helps but does not work as good."

If you've got any mp3 files in iTunes, re-encode them as AAC, I found that all the files that cause this are mp3, not all mp3 files do this but some do, I had exactly the same problem and re-encoded my mp3 files and, problem solved!

Simply turn off 'Gapless Playback' alltogether in iTunes preferences.