Why can't I synchronize my iTunes library after formatting/reinstalling OSX? I plugged in my iPhone to get all my music back onto my iMac & it told me it is synced with another library & I would have to erase its contents to resync.
iMac (20-inch Early 2008)
That is completely normal, since after reformatting and reinstalling Mac OS X, you now have a blank copy of iTunes which appears as a completely different library for your iPhone. To get the content from your iPhone, see this support article:
http://support.apple.com/kb/HT1848
You can also download most of your content (the notable exceptions being movies, some of which can be redownloaded if you're in the US, and audiobooks) again from the iTunes Store:
http://support.apple.com/kb/ht2519
For content not purchased from the iTunes Store, check out this post from Zevoneer for some iPod/iPhone media recovery options:
http://discussions.apple.com/thread.jspa?messageID=10570955#10570955
Regards.
Syncing an iTunes library from an iPhone after a format -- HELP!
