ITunes Match mismatch between OS X and iOS

You may not be able to get complete matches, but here's what I have been doing in the cases where one or two tracks don't match.

1. Select the item(s) to attempt to re-match.
2. Right-click on them, and select "Create AAC Version"
3. When this is complete, hit alt-backspace, and choose to remove both the original and the iCloud version. Also choose to delete the items from disk.
4. Go to the "Store" -> "Update iTunes Match" menu item.

Note that this will keep the play counts, etc on your tracks. It may not succeed on every track, and sometimes repeating the process picks up another track.

Occasionally, I'll get a "Removed" icon there after doing this: just right-click and choose "Add to iCloud" on these.

It's been confirmed elsewhere that metadata alone will not give success in matching (if it were, someone would quickly find a way to just create thousands of dummy files with the right metadata). Some audio fingerprinting is going on, and you can test it by changing the metadata of one track to that of another one, and see if if matches the audio or the metadata. Still, metadata plays a role as well.

MacWorld have a note on the problem of one or a few songs not matching from an album: Basically, it seem to affect specific songs (rather than just randomly failing every n:th song). Two possible reasons for this:

1. The audio or metadata specific to that track confuses the matching algorithm (as we know, audio fingerprinting is not an exact science)
2. There is a rights issue with particular tracks that Apple haven't been able to find agreement for.