That message is limited in its helpfulness (I know, I've had the same problem that you are now reporting, except that it involved far more songs). When iTunes offers to find the additional missing songs, it looks in the same folder as the one you navigated to when you found the song you were looking for. So if the songs are not in that same folder, iTunes still won't find them.
When you next see the message, check the + list and see whether you can spot a common theme with the missing songs. Are they all from the same artist, or the same (various artists) compilation album for example? If they are, or if you do see a common factor, that may help you find the song entry in your Library. For example, if all the songs are from the same artist, but from different albums (so in different sub-folders), you can then check them in your Library to see whether they play. As you probably know, if you ask iTunes to play a song, but it cannot find the file for it, it places an exclamation mark next to the song title. If you get to that stage, you can then use iTunes' error message to navigate to the correct folder, based on the usual folder structure that iTunes uses.
You may well know this, but generally, when iTunes downloads songs from the iTunes Store, or copies them from CD, it puts the files for the songs into folders based on the artist name, and then a sub folder for each album, all within the iTunes folder. I realise it may not if you have bought songs from Amazon for example. That will depend upon where you put them.
One thing that might reduce the time taken to find the songs is that if you find another missing song and then ask iTunes to check again, it will check in that folder, not the one it looked in last time. For example:
- you manage to find one song and get it back into your library. Once that's done, you agree to iTunes' suggestion that it look for the other songs, but when it checks that same folder, it finds no additional missing songs
- but the next time you look for a "missing song", because the song is in a different folder to the last one, you look in that different folder, so when iTunes checks that folder for additional songs, it finds one or two more of the missing ones, thus reducing your list by three instead of one. (It's a long shot, but you never know...)
It's irritating, I know. Unfortunately, it's simply what one has to go through sometimes, in order to maintain a library of music, particularly if you have a large library.