Inspired by an iPod shuffle second generation of which we had to define the owner - the device was simply named SHUFFLE and could be anyone's from the house (5 potential owners).
iPod shuffle back to iTunes or Mac
1. When you plug in an iPod shuffle to a Mac that it hasn't been used with and the warnings you get aren't helpful.
If we choose either we are doomed. Canel.. well and the iPod won't charge, and it won't be seen in iTunes. Erase and sync.. and we will never find whose iPod it was because we can't find out whose music and files it had. Therefore, hide iTunes (command-h). This is the first step.
2. Take note of what Finder shows for the name of the shuffle.
3. In Finder, Go > Go to Folder... /Volumes/SHUFFLE/iPod_Control/Music/F00 where SHUFFLE should be replaced with whatever your Finder shows as the name for your shuffle. This will open a window with all your music in that hidden folder.
4. Repeat for /Volumes/SHUFFLE/iPod_Control/Music/F01 and /Volumes/SHUFFLE/iPod_Control/Music/F02.
5. Now you have 3 Finder windows open with all the music on that iPod showing (not necessarily with correct filenames). If you simply need to figure out whose iPod it was, listen to something in Finder's preview and see if anyone recognizes by the music. (Of course, if the iPod had charge, this could have been done without the Mac to start with).
6. To get the music back to your Mac before erasing and syncing it - Open one more Finder window where ever you want to bring these music (for instance in yourhomefolder/Music/ create a new folder 'Music from shuffle' or something similar. Now simply drag and drop the music from the folders F00-F02 to this folder. You will not be able to drag them directly to iTunes, since it will still be wanting you to eject the iPod or to destroy all the music in it. After the files are copied, done. (In this particular case, it was my Shuffle, and I didn't have the music I had on this iPod on my Mac mini as the Mac I had used this iPod the last time had been at work).
7. If considering to erase and sync the iPod, verify in Finder that you don't have any visible folders in the iPod with other data. If this would be the case, copy also those files and folders, and when all done, go back to iTunes or simply eject the iPod from Finder.
You could do this also with Terminal, cd /Volumes/Volumename and to the same paths as below, then copy them with cp, but unless you know exactly what you would be doing in Terminal, I recommend using simply Finder as above. It will do the job.
Other iPods back to iTunes
There is probably a more sophisticated method than the above also for the shuffles. But as plain steps in Finder that will work for that situation.
For non-shuffles we have more options.
1. Similar to above. The files are in similar but slightly different locations, depending on iPod model. For 20 GB iPod, you will have 20 hidden folders, so you probably don't want all of those open at the same time.
To do the copy manually, verify the locations of these folders with Terminal.
Find where the hidden folders are, and copy with Terminal or Finder or however you like.
2. Other alternatives - use programs that will get your music back from your iPod to your Mac.
There are a number of software that can do this:
* Senuti (beta) http://www.versiontracker.com/dyn/moreinfo/macosx/23390
* Synch iPod-iTunes Data (freeware) http://www.versiontracker.com/dyn/moreinfo/macosx/22152
* iPod.iTunes (shareware) http://www.versiontracker.com/dyn/moreinfo/macosx/14323
* iPof for Mac (shareware) http://www.versiontracker.com/dyn/moreinfo/macosx/32900
I remember also using some other freeware for this in 10.2 nut forgot its name...
As the basic for getting your stuff from your iPod back to your Mac is quite simple, I'm surprised there are so many sharewares to do this.
iTunes won't do the transfer of anything from your iPod back to iTunes and this is a design choice, inspired by the music industry. There are times when you need your stuff back to your mac, when your forgot to keep a backup of the music you had, or when your hard drive died, or when your iPod is 160 GB and your Mac's hard drive only 40 GB and so on.
Still - your music is valuable (for you), and it's best to keep all your valuable data in a good backup. If your internal hard drive isn't big enough, get an external one, they are not that expensive and it does not have to be on all the time either. Make backups regularly. And don't keep your music only on your iPod. It also has a hard drive or flash drive - if that would die, you'd be out of luck, and have worst case 160 GB of your music and movies gone. *Puff* And your computer backups if they were on that iPod. Especially if your backups are on the iPod, do keep them also in an external hard drive (or server or tape drive or whatever you trust and have)/
If you take your Mac to repair, or do any hardware repairs on it, deauthorize iTunes. Also this should reduce the risk of you ever needing to get your stuff with the above methods back to your Mac.
Most of these could be applied for doing this also in Windows.
However I can't navigate as fluently there... you could use cmd to find the locations of the hidden folders, and copy the files with that or Explorer.
And for the programs, there are several shareware options for this backward sync from iPod back to your PC or iTunes in Windows.
http://www.versiontracker.com/windows/ will find them, just search for the keywords.
And the last piece of advice. If you need to bring any file from one Mac to another Mac (or pc), do it like you were transferring non-music files. Drag the files or folders in Finder (Explorer for Windows) in it. This way, you won't have access to listen to these files while you are listening to the iPod, but you can get them where ever you needed to get them to, and later add them to your iPod using iTunes.
My last words would be the same as in the stickers coming with the iPods - don't steal music.
iPod shuffle back to iTunes or Mac
1. When you plug in an iPod shuffle to a Mac that it hasn't been used with and the warnings you get aren't helpful.
If we choose either we are doomed. Canel.. well and the iPod won't charge, and it won't be seen in iTunes. Erase and sync.. and we will never find whose iPod it was because we can't find out whose music and files it had. Therefore, hide iTunes (command-h). This is the first step.
2. Take note of what Finder shows for the name of the shuffle.
3. In Finder, Go > Go to Folder... /Volumes/SHUFFLE/iPod_Control/Music/F00 where SHUFFLE should be replaced with whatever your Finder shows as the name for your shuffle. This will open a window with all your music in that hidden folder.
4. Repeat for /Volumes/SHUFFLE/iPod_Control/Music/F01 and /Volumes/SHUFFLE/iPod_Control/Music/F02.
5. Now you have 3 Finder windows open with all the music on that iPod showing (not necessarily with correct filenames). If you simply need to figure out whose iPod it was, listen to something in Finder's preview and see if anyone recognizes by the music. (Of course, if the iPod had charge, this could have been done without the Mac to start with).
6. To get the music back to your Mac before erasing and syncing it - Open one more Finder window where ever you want to bring these music (for instance in yourhomefolder/Music/ create a new folder 'Music from shuffle' or something similar. Now simply drag and drop the music from the folders F00-F02 to this folder. You will not be able to drag them directly to iTunes, since it will still be wanting you to eject the iPod or to destroy all the music in it. After the files are copied, done. (In this particular case, it was my Shuffle, and I didn't have the music I had on this iPod on my Mac mini as the Mac I had used this iPod the last time had been at work).
7. If considering to erase and sync the iPod, verify in Finder that you don't have any visible folders in the iPod with other data. If this would be the case, copy also those files and folders, and when all done, go back to iTunes or simply eject the iPod from Finder.
You could do this also with Terminal, cd /Volumes/Volumename and to the same paths as below, then copy them with cp, but unless you know exactly what you would be doing in Terminal, I recommend using simply Finder as above. It will do the job.
Other iPods back to iTunes
There is probably a more sophisticated method than the above also for the shuffles. But as plain steps in Finder that will work for that situation.
For non-shuffles we have more options.
1. Similar to above. The files are in similar but slightly different locations, depending on iPod model. For 20 GB iPod, you will have 20 hidden folders, so you probably don't want all of those open at the same time.
To do the copy manually, verify the locations of these folders with Terminal.
Find where the hidden folders are, and copy with Terminal or Finder or however you like.
2. Other alternatives - use programs that will get your music back from your iPod to your Mac.
There are a number of software that can do this:
* Senuti (beta) http://www.versiontracker.com/dyn/moreinfo/macosx/23390
* Synch iPod-iTunes Data (freeware) http://www.versiontracker.com/dyn/moreinfo/macosx/22152
* iPod.iTunes (shareware) http://www.versiontracker.com/dyn/moreinfo/macosx/14323
* iPof for Mac (shareware) http://www.versiontracker.com/dyn/moreinfo/macosx/32900
I remember also using some other freeware for this in 10.2 nut forgot its name...
As the basic for getting your stuff from your iPod back to your Mac is quite simple, I'm surprised there are so many sharewares to do this.
iTunes won't do the transfer of anything from your iPod back to iTunes and this is a design choice, inspired by the music industry. There are times when you need your stuff back to your mac, when your forgot to keep a backup of the music you had, or when your hard drive died, or when your iPod is 160 GB and your Mac's hard drive only 40 GB and so on.
Still - your music is valuable (for you), and it's best to keep all your valuable data in a good backup. If your internal hard drive isn't big enough, get an external one, they are not that expensive and it does not have to be on all the time either. Make backups regularly. And don't keep your music only on your iPod. It also has a hard drive or flash drive - if that would die, you'd be out of luck, and have worst case 160 GB of your music and movies gone. *Puff* And your computer backups if they were on that iPod. Especially if your backups are on the iPod, do keep them also in an external hard drive (or server or tape drive or whatever you trust and have)/
If you take your Mac to repair, or do any hardware repairs on it, deauthorize iTunes. Also this should reduce the risk of you ever needing to get your stuff with the above methods back to your Mac.
Most of these could be applied for doing this also in Windows.
However I can't navigate as fluently there... you could use cmd to find the locations of the hidden folders, and copy the files with that or Explorer.
And for the programs, there are several shareware options for this backward sync from iPod back to your PC or iTunes in Windows.
http://www.versiontracker.com/windows/ will find them, just search for the keywords.
And the last piece of advice. If you need to bring any file from one Mac to another Mac (or pc), do it like you were transferring non-music files. Drag the files or folders in Finder (Explorer for Windows) in it. This way, you won't have access to listen to these files while you are listening to the iPod, but you can get them where ever you needed to get them to, and later add them to your iPod using iTunes.
My last words would be the same as in the stickers coming with the iPods - don't steal music.