Restore previous app/music after rebuilding library

Question

I recently chaged drive location to all my music (23000+ mp3) on my pc: ie: from D:\music to E:\music
To avoid adding again all the music from scratches to iTunes I decided to just rebuild the library after mass-modifying the paths in the xml file (if you don't know what I'm talking about check this: https://discussions.apple.com/message/11566523?messageID=11566523#11566523). Of course I had previously made a backup of all the library files (iTunes Library.itl iTunes Music Library.xml iTunes Library Extras.itdb-mj0B573865 iTunes Library Extras.itdb iTunes Library Genius.itdb sentinel)
The trick worked well: all my music was back with references pointing to the new location.
The problems arised when I plugged in my iPhone 4 (osx 5.0.1)... basically 2 problems:
1) The app tab inside itunes doesn't show the apps I had, even if all the apps are in C:\Users\****\Music\iTunes\iTunes Media\Mobile Applications.
Not a big deal as itunes ask me if I want to move my purchased apps from iPhone to the PC... so it is possible to solve this problem but it's not the best solution as it takes a lot of times to copy the apps back and it does create duplicates (ie after starting moving some apps I have Adobe Reader 10.1.0.ipa and Adobe Reader 10.1.0.1.ipa and of course the one linked in the apps tab is the latter.. ). Nothing big, but I wish my iTunes could just see the apps since they still are in their place.
2) Similar but worse problem with music: iTunes has just forgot which music I had synced with my iPhone.
Of course the music is still on my HD (in a new location, but this location is "known" by the library file) but when I go to the music sync panel under my iPhone panel, I see only some playlists are selected whereas I had mainly manually selected some full albums. So now I have two options: sync only the playlists (392 songs) or syncing nothing. In both cases most (all in the latter case) of the music on the iPhone would be erased and I would need to manually select the files again and resync. Nothing terrible, but quite time-consuming as it was a lot of music within a huge library (2800+ files among 23000+).
NB: If I restore the backup of all the 6 files mentioned above, songs are correctly selected and apps are correctly seen.. but of course songs point to the wrong location (and I really don't want to manually update location of 23000+ files ). So these information are not somewhere else than the 6 files.. maybe in one of the Library Extras file... which are unfortunately rebuild together with the main library.. so how can I rebuild the Library without loosing those information? Or alternatively, is there any othr way to automatically update location of all files?

Answer 1

I recently changed drive location to all my music (23000+ mp3) on my pc: ie: from D:\music to E:\music
Why? Assuming drive E: is bigger to accommodate an expanding library is there a good reason why, having cloned the media across to it, you didn't then swap the drive letters around? This would be a lot easier than messing with the XML file rebuild trick which, as you have found, has a number of drawbacks.
If reassigning drive letters doesn't suit you then do this:
Restore the original library files.
Open iTunes, play a song, (forces it to update the database), close iTunes
Copy the files iTunes Library.itl, iTunes Library Extras.itdb, iTunes Library Genius.itdb, sentinel and the folder Album Artwork to D:\ (ignore the xml and bonus extras file)
Click the icon to start iTunes and immediately press and hold down the shift key. You should be asked to choose or create a library. Click Choose and open the library file D:\iTunes Library.itl
Check that the library is working properly by playing a track. Close iTunes.
Copy the files iTunes Library.itl, iTunes Library.xml, iTunes Library Extras.itdb, iTunes Library Genius.itdb, sentinel and the folder Album Artwork from D:\ to E:\
Shift-start iTunes and open the library file E:\iTunes Library.itl
Check that the library is working properly by playing a track.
Use the menu command File > Library > Organise Library > Consolidate files to catch any stray references to files outside your media folder.
Use the menu command File > Library > Organise Library > Rearrange files in the folder <media folder> (if available) to update the structure of your media folder.
Close iTunes, rename E:\Music to E:\iTunes Media, start iTunes.
Check media still plays.
Close iTunes, create a folder called E:\iTunes, then move iTunes Library.itl, iTunes Library.xml, iTunes Library Extras.itdb, iTunes Library Genius.itdb, sentinel and the folders Album Artwork & iTunes Media from E:\ to E:\iTunes
Shift-start iTunes and open the library file E:\iTunes\iTunes Library.itl
That's all folks.
Your library is now properly organised and self contained on drive E:. Next time you want to move if just copy the whole thing in one go to a new location of your choice and use the shift-start-iTunes method to open it. Or you can change the drive letter of this drive and when iTunes complains that it can't find the library you can browse to the new X:\iTunes and the library will work correctly. You can backup the folder E:\iTunes to another drive or network share using this User Tip and that backup will be a fully functioning copy of your library on whatever path you choose to keep it.
tt2