iTunes to iPhone "Unknown error 0xE800007F"

I think gokay05 is correct--and that's the bug. Even when the iOS device is not plugged in to power, it shows up in iTunes and iTunes does seem to try and sync and aborts because no power. While this may be working more or less as designed, the net result is an accumulation of error messages on iTunes. It has another unfortunate aspect and that is you can't close iTunes. With the boxes checked to sync when on power and open iTunes when this device is trying to sync, the result is that iTunes keeps opening even when none of the iOS devices is connected to power. It seems to me that at a conceptual level the fix needs to be for none of these steps to occur unless the device is connected to power. That's not the present state.

Both my iPhone and iPad connect to my PC and attempt to sync when not connected to power. In fact, thats the only time I get this error. If they are connected to power, they sync with no error whatsoever.

But that might be where the problem is. The software is trying to sync when it asks the device if it is powered up and the device says no, so the sync fails.

Im sure Apple will release an update for iTunes that tells the software to abort sync if the device is not connected to external power rather than try to sync until it fails.

First off, YES iPhone 4S DOES try to (and successfully does) sync up even when not connected to power cable, regardless of what the instructions say. Just like with PhotoStream and iCloud, when my iPhone is connected to wi-fi, it tries to connect to my PC, regardless of being plugged in or not. That's a FEATURE, in my mind. One that I assume they will "fix" when they patch it.

2ndly, I am experienceing mostly the same issues with this error. (Win 7, 64bit, ios5, icloud, iPhone 4S, newest iTunes)

The problem is intermittent. Sometimes happens when phone is plugged into charging cable, sometimes when it's not. Error message indicates no sync, but when I click "okay" the sync eventually initiates again and often works fine. It's irritating, but not debilitating. I'll roll with it until the patch fix.

iPhone does sync when not connected to external power ONLY if the sync is initiated manually by hitting "Sync Now" under settings. iPhone will not sync automatically when not connected to external power. Connecting to your PC is a feature but the syncing is not. When the iPhone is connected to iTunes, it should not initiate sync when not connected to power. If you power up your device or start iTunes while the device is powered up, it will automatically sync but when it is not, it tried to sync, fails and gives the error code.

Not in my case. I get automatic itunes syncing when I have wi-fi connectivity, and when my itunes is already opened. And sometimes it fails, and I get the error message and sometimes it is successful. Just like when wired.

I have the same error messages popping up randomly. It's not just the unknown error, occasionally it will be a different error. Sometimes I have to click through 2 or more messages to use iTunes. Very annoying. Just wanted to add my voice to the choir - please fix!

The error is that it cannot CONNECT to the device, not that it can't sync to it after connecting.

What's interesting is that iTunes eventually does connect and all is well after you acknowlege all of the error messages that stack up.

+1 for hoping they release a fix soon.

Does everyone having this problem also use a lock code on their iPhone? If you're using a lock code, try disabling it and see if the error re-occurs.

I used to have tethered sync problems with my iPhone and Windows-based iTunes, and the lock code was the problem. I haven't tried disabling my lock code for this error yet. Worth a try.

Disabling the lock code does nothing to stop this error for me.

No - I don't have a lock code on my iPhone, but still experience the problem.

ok same here.. i updated to os5 and not able to sync since..and itunes keeps opening up without been connected to my iphone?

however.. also i have a nother problem with imessage - a random person can see all my imessages.. any fixes yet tryed login in/out of itunes

updated to 5.1

and its not a voda issue as its the same with orange and o2 .

please help!

Same problem here. It automatically tries to sync, whether iphone is plugged in or not. And the message seems completely random; sometimes it works, sometimes it doesn't.

ditto to everyone else's post. what's going on apple? I can not sync via itunes wifi. this is lame. please fix this via a patch. i do not want to restore my phone again! think WWSD... What Would Steve Do!

I've just installed iTunes v10.5.1, I'm stll getting error, infact it seems a lot worse. I've had to disable wifi sync on my iPhone now.

add me to the list. Itunes 10.5 is nothing but bugs. It was fine in 10.4 prior to ios5....I have 30k songs, ipad2 and iphone 4 - I get this error all the time. Also - itunes opening takes 5 min to load up 'checking my library'