After I add a pdf to my Library, and check Sync Books, when I try to Sync/Apply I get a warning message: The iPhone is synced with another iTunes Library. Do you want to erase this iPhone and sync with this iTunes Library. Erasing sounds threatening.
I added a pdf to my iTunes Library. Next, I checked Sync Books (tried both ALL and SELECTED options). When I select APPLY I get an error message that my iPhone is synced with another iTunes Library. And do I want to erase my iPhone and sync with this Library. Frankly, erasing my iPhone sounds very threatening and not for the faint of heart. What happens to all my data and settings?
iPhone 4, iOS 6.1.2