Yesterday I tried to load some music on my iPhone for the first time in a year. The result was a complete iPhone apocalypse. Long story short; at some point iTunes decided to do an incredibly long and slow sync of some music I didn't want to copy. With no progress bar, no indication of how long it'd take, and no cancel button. So I did the only sensible thing and unplugged the phone.

The result? Not only did I have no music on my phone, but now I had no third party applications, either. Well I had a couple, some random subset were left behind. The other apps were deleted. Along with their data. Including a month's pain-stakingly collected diet data, gone forever.

Two-way sync is hard. But it's not that hard. iTunes' model is apparently that it has the canonical copy of what's on your phone. Only it doesn't update that model correctly in all cases, and then deletes whatever is on your phone that doesn't match the incomplete copy on iTunes.

I can sort of understand that failure with the music library; your iTunes install is the only conduit for putting music on to the phone. But apps can be installed independently, and generate their own data on the phone. iTunes can't be sure it has seen all the app data; so why be so casual about deleting it? Even if you can count on the user not to unplug the phone mid-sync, what happens if iTunes crashes? Or the machine crashes? Or the cat knocks over the phone? Or the power goes out?

I've made a sport of iTunes-bashing on my blog and Twitter the past few years. It's a bit obnoxious, but every time I try to use iTunes I'm stunned at how bad it is, particularly on Windows. Apple's reputation of building humane, user-friendly software is completely misplaced in this case.