The ipad cannot be synced. An internal device error occurred.

Yesterday I updated my iPad Pro 9,7" to iOS 11. All went well. But when I thought I was entering my Apple ID for iTunes, I was tricked into iCloud. I never use iCloud. Not on my iMac and not on my iPad. I just don't want to use it.

When I opened my unwanted iCloud account every button was set to ON. It took me a lot of time to set every button to OFF. In the meantime a lot of my documents (photos) were copied to iCloud. I had to delete them from my iCloud Drive. After I logged out of iCloud I discovered that all my photos were deleted from my iPad.

Of course I had a backup on my iMac. I always sync my photos (and books and music) with iTunes on my iMac. I have updated iTunes to the latest version.

Never before I have had problems with this procedure. But this time all went wrong. It said there was no iBooks App and no Music App on my iPad and after that I discovered that all my books and music was deleted on my iPad.

Several times I got the message "The ipad cannot be synced. An internal device error occurred."

I tried all the usual things - restarted the iMac and the iPad / changed the cable (all Apple cables) / changed the USB port. I succeeded in restoring my books and my music but not my photos (more than 3000). It stops halfway with the above message and than only a few hundred photos are copied.

Before iOS 11 syncing with iTunes always worked great. Now I don't know what to do to solve this problem.