The iPad cannot be synced. An unknown error occurred (1140).

Question

Since updating my iPad to iOS 6 and updating iPhoto to 9.4, I have been receiving the error The iPad <name of my iPad> cannot be synced. An unknown error occurred (1140).
The syncing seems to be centered around photos. I used to have the box checked next to "Sync Photos from iPhoto" and now the only way that I can get the iPad to finish sync without error is to uncheck that box.
Any ideas how to fix this problem or what that code is?
A couple things that I should mention:
1) Photo Stream is Off on my iPad.
2) If you click on the Photo app it shows that there are no photos on the iPad. Screen says No Photos or Videos - You can take photos and videos using the camera, or sync photos and videos onto your iPad usining iTunes.
3) If I go to Settings > General > Usage > Photos & Camera it shows that I have 4.2 GB of data used by photos and camera. Clicking on it, it shows that 3.7 GB is Photo Stream and 551 MB is Photo Library.
4) If I got to the same usage screen on my iPhone 4 running iOS 6, Photo Stream is listed as 1.5 GB.
I can't seem to figure out how to get rid of the space on the iPad, but I assume this error as something to do with iTunes thinking there is a library on the iPad that isn't there. That's just me assuming though.
Any help would be greatly appreciated.

Answer 1

I'm having the same issue.  After updating all iOS devices to iOS 6, then updating all software on my iMac to the latest versions (including iPhoto 9.4), everthing was working as it should.  I was able to sync all of my devices (New iPad, iPod Touch, iPhone4) with the iMac early this morning.
Subsequently, I opened iPhoto for the first time since installing 9.4, a window popped up informing me that my photo library had to be converted to work with the iPhoto 9.4.  I clicked okay, and let the conversion process run its course.
About ten minutes later, I attempted to once again sync my iPad with the iMac.  The sync process would run for a few seconds, then stop with a window popping up saying "The iPad cannot be synced. An unknown error occurred (1140)".  I then attempted to sync the iPod and my iPhone, with the same results.
After consulting the discussion forums, it looked like lots of other users are encountering the same problem, and that it was somehow related to the new iPhoto.  Someone suggested turning off syncing photos from iPhoto, which I did.  With photo syncing turned off, the rest of the sync program now runs without a problem.
I've submitted a bug report to Apple.  Hopefully, enough other users have done the same, and Apple will fix whatever it is that's causing the problem.