No. of Discs or Part of a Compilation . Tiny differences such as trailing spaces, accented characters or variants of symbols can sometimes be quite hard to spot. The iPod is also more sensitive to case variations and may split, duplicate or reorder an album that looks okay in iTunes. Normally overtyping the desired value for each shared field will complete the grouping of the album into one entity. Occasionally, however, this method seems to fail. When this happens I've found that you can force every field to update properly by adding some extra text - e.g. a trailing X , which once applied seems to complete the joining of the tracks into one album. Once this has happened the extra data can be removed and the album should remain properly grouped. Multiple tags The ID3 specifications allow files to have multiple tags in different versions and languages, but iTunes only works properly with single tags. When multiple tags are present it can sometimes fail to apply updates to the tag that it reads back (presumably updating one of the others in the file) and it is also possible that iPod & iTunes may have different rules for which tag they give priority to. This could lead to situations in which everything is properly organised in iTunes but then inexplicably falls apart on an iPod. There are 3rd party tag editors that can manipulate multiple tags but I don't have a recommendation offhand. A workaround in iTunes is to use