Q: Hello everyone, I need some assistance. I have searched but cannot find conclusive evidence of a resolution to my issue. I hope someone here can help. I have both a first and second-generation iPod touch. I used to sync both with our PC in Windows XP. Well, that PC died. Lucky for us the hard drive was intact. So now I was hoping I could transfer my iTunes applications and music to my new Macbook (OS X 10.5). Well I have heard that it is easy and I heard that I will lose everything if I do so. What I am most concerned with is I do NOT want to lose my data in my apps.
I have lots of things built up that do not back up outside of the iPod touch, like my complete workout and routine along with a log of all my workouts plus my shopping list with all of the aisles worked in it. I want to keep my game saves too. How can I transfer without losing it all? Is it even possible? Or should I just make a backup of my info and have my PC fixed and wait till it is back up and running?

– Anonymous
A: Firstly, it is important to note that iTunes associates your iPhone and iPod devices not based on the physical computer, but rather based on the library database, so if you transfer your entire iTunes folder to a new computer, any existing iPods will continue to sync with the new computer in the same way as for the older one—the device associations are stored in the database itself. The catch in your specific situation, however, is that migrating an iTunes library database smoothly between different operating systems (ie, Windows/Mac) is complicated, as the path structures are completely different, so although iTunes can read the library database, it will not be able to locate any of the specific media files, as it will be using pathnames based on the other operating system (for instance, Mac OS X doesn’t know what a C: drive is). In this case, you will probably find it far simpler to start a new iTunes library database and reimport your music and media files from your Windows computer or from your iPod touch, depending on which is easier.
Also note that the data and settings on your iPod touch are in fact normally backed up by iTunes. This backup includes all of the settings on your iPod touch, data from the built-in applications and data from any third-party applications that you have installed. In fact, the only information that is not stored in this backup is the media content that is synced from iTunes itself, since this would be much too large to backup on a regular basis, and iTunes logically assumes that you could re-sync this information from your iTunes library.
Note that this information is not stored directly under the iTunes folder, but in a separate location on your hard drive under your home profile folder in the Application Data\Apple Computer\MobileSync\Backup folder. You can see the backups that iTunes has stored for any iPhone and iPod touch devices by going into your iTunes Preferences and selecting the “Devices” tab:
While you could simply migrate this folder from your Windows drive over to your Macbook, the reality is that it’s far easier to re-backup your iPod touch to the iTunes library on your Macbook than dealing with transferring the backup information.
Although iTunes will only automatically backup an iPod touch that is associated with the current library, any computer running iTunes can manually backup your iPod touch, regardless of whether you have previously synced your iPod touch with that computer or not. To backup your iPod touch manually to another computer running iTunes, simply connect the iPod touch to that computer and then right-click on the iPod touch in the Devices list on the left-hand side of the iTunes window and choose the “Backup” option from the context menu:
If you have been syncing your music and video content to your iPod touch automatically from your primary iTunes library, then when you first connect your iPod touch to a new iTunes library you will be prompted with a note informing you that your iPod touch is already associated with another iTunes library database and asking you what you want to do:
The “Cancel” option will essentially perform no sync operations at all, but will leave your iPod touch connected and visible in your iTunes application so that you can perform other tasks on it, such as making a backup (as described earlier) or setting it into manual mode, which may be useful if you’re only looking to add/remove a few music and video tracks while you’re waiting for your PC to be repaired.
The “Transfer Purchases” option will copy any information that was purchased from the iTunes Store from your iPod touch back to the current iTunes library. This includes any purchased music or video files as well as all of your applications. Note that the “Transfer Purchases” option will only appear if there are in fact purchased items on your iPod touch that are not already in your iTunes library and the new computer has been authorized for the iTunes Store account that was used to purchase these items. You can authorize your computer manually simply by choosing Store, Authorize Computer from the iTunes menu and entering your iTunes Store username and password.
The “Erase and Sync” option will erase all of the media content, such as music and videos, from your iPod and replace it with the content in the current iTunes library. Note that this only affects content such as music and videos—it does not affect information such as stored photos or applications you have installed on your device. Existing applications and their data are not removed from your device unless you specifically choose the option to RE-sync your applications on the “Applications” tab. If you do choose to do this, iTunes will still warn you that you are about to replace all of the applications on your devices with those in the current iTunes library.