Windows – how do i “check” the songs in Itunes

I doubt iTunes is directly involved. iTunes edits your metadata when you tell it to do so by using the built-in id3 tagger or the fetch cover function. iTunes updates other information like playcounts or ratings in a separate database file that doesn't affect songs metadata.

I suggest the next time you see a such badly tagged mp3, you investigate using an id3 editor (eg Tag and Rename) :

• are the ID3v1 tags synchronized with the ID3v2 tags ?
• if ID3v2 are present, which version is it? 2.2? 2.3? 2.4?
• try to spot oddities that could confuse players : many covers embedded, huge size of the comment field, etc

So I suggest that it's one of those corner case that iTunes happen to process well and not your other player. But to answer more directly to your question, if you think that some process has altered your metadata, you can set the files as read-only to prevent any modification.

iTunes has no functionality to actually scan for missing songs from it's library. If you want to delete Music, you need to do it from within iTunes, and not the other way around. It can however identify missing files which normally appear with an ! mark next to their names. These can simply just be deleted out of the library manually.

There are some 3rd Party options to try and do this automatically:

• AppleScript Scan Missing is an AppleScript solution if your using a Mac or this AppleScript from MacOSXHints.

• For Windows you can use the iTunes Library Scanner mentioned in this iLife article.

Once you have removed the songs from the iTunes library, they will be removed of your iPod the next time it synchronizes.