My friend updated iTunes by mistake and now it is incompatible with one of her other devises. She now has version 12.2.2.25 (really? How many incremental changes do you make?) Is it possible to get the older version re-installed without a nuke and pave and will get music ever still work in that version?

When I upgraded to El Cap I installed (drag & drop) the version of iTunes I was running in Snowy, so as far as I can see your friend should be able to revert her version of iTunes similarly...without resorting to nuke & pave (because iTunes doesn't sink its hooks into OS X like some other apps do), but...

1. She'll need a source from which she can extract (using Pacifist if necessary) an older version of iTunes, with which she'll probably be stuck.
2. Her current iTunes Music Library won't run with the older version of iTunes, so she'll have to reimport all of her music.

Edit: If your friend has got her Mac backed up she should be able to use the version of iTunes in the backup's /Apps folder, and she should also be able to import whatever she needs from ~/Library/iTunes, her original "iTunes Music Library" in particular.

Afterthought: She maaay find her original iTunes Music Library in her current iTunes folder, and although it will have been renamed, it can be reverted.

She NEVER backed up. Don't know where to get older iTunes, s/b 11.0.4

Find somebody who's running the version you need, copy it from hir /Applications folder to a disk, and drag & drop it into your friend's /Applications folder. (I've got iTunes 11.4 in my Snowy installation if you can use it.)

I am running the version she needs, so I get this Pacifist whatever to extract the program and then import her music? Someone told me the music files change but they must have not imported the music, just dragged the folder over...

You can download installers from Apple's download pages. They list 11.4 for Snow Leopard and 10.7 for earlier: https://support.apple.com/downloads/itunes

1. If you're running the exact version your friend needs you don't need Pacifist; all you need to do is burn it from your /Apps folder to a disk, and drag & drop it from the disc to her /Apps folder (although it would probably be better to d/l v 11.4 from Apple as per freelance if that version is OK). I'd repair permissions after reinstalling.

2. You'll need to get rid of the version of iTunes.app (only) that she's got installed now in one way or another, and it may be a pain depending on which version of OS X she's running.

3. When your friend upgraded iTunes her ~/Music/iTunes/iTunes Music Library.xml was changed to a version that's not compatible with the earlier version of iTunes you're going to (re)install, so you'll have to either recreate or reinstall the lost file:

• I believe the original of that file still exists in ~/Music/iTunes, but with a changed name, in which case you can change it back to iTunes Music Library.xml.
• If not, you'll have to reimport her entire ~/Music/iTunes/iTunes Music folder, and that will result in its being recreated.

In either event you'll want to trash the new file.

Hope that helps.