iTunes backup not enough storage

Turns out there were one or more corrupted files on my iPad. iTunes would start the backup, run for a couple of minutes, then die with the "not enough space" message. In fact, it was running into one or more files that were reporting an incorrectly high size. Ended up depending on iCloud backup, then did a restore of the system from iTunes, followed by a restore from iCloud. All is well now.

I was wanting the backup to my local computer because it has been my experience in the past that iCloud backup does not save all app data. That appears to be not true anymore. A backup to iCloud is just as good as one to local storage via iTunes.

What clued me in: I installed the iExplore app to see if I could figure out what was wrong. iExplore was telling me that the iPad was using something like 200+GB of the available 256. iTunes thought only 80GB was used. Even after I made more than 256GB of free space available on my Mac, it still failed.

Hmmm. For some reason, I'm unable to restart in Safe Mode. Tried several different ways - including unplugging everything from my MacBook Air (mid 2012) while trying a restart with the Shift Key held down. Always starts in "Normal" mode. I'll have to see if I can get in touch with Apple Support.

The message in General / iPad Storage says "61.7 GB of 256 GB Used." You'll see a similar message on an iPhone. One can surmise that there's about 194 GB free. I have almost 100 GB more than necessary available on my Mac.