TUAW reader Jamie Phelps has possibly stumbled upon a nasty iPhone synching bug when keeping one's iTunes library on an external hard drive. While tips like our how-tos for setting up iTunes with external drives or even an AirPort Disk work pretty well even when synching iPods with them, Jamie found that his iPhone gets the brainwash treatment when he's away from the drive containing his external iTunes library. As the story goes, Jamie synched his iPhone with a few songs and playlists, made a couple new playlists and then synched again. Hitting the road, however, and getting away from his external iTunes library drive is when the bug rears its nasty head: plugging the iPhone in while on the go caused iTunes to wipe out the new playlists and songs from the second sync operation, basically reverting them to their state before the second sync. To verify, Jamie even got adventurous and tried this whole thing a second time, once again watching iTunes blow away changes from the previous iPhone sync when the external media library isn't mounted.
This is the first time I've heard of iTunes handling this kind of setup in a poor way; for as long as I can remember, iTunes has been clever enough to realize what's happening and and would either not sync anything to an iPod when away from the library drive, or it would actually sync any media downloaded or imported while away (as we've mentioned before, you can use the Advanced > Consolidate Library command to move all this new media once reconnected with the library drive). Since we don't really have any evidence of Apple deliberately changing this behavior for their iPods or iPhones, it makes sense for this quirk to be classified as a bug that will hopefully be squashed with an inevitable iPhone software update. But what say you, TUAW readers? Anyone else get bit? Sound off.