Venkat1954 wrote:
Bob, thanks for the tip. I downloaded OmniDIskSweeper and discovered at least part of the problem. My MobileSync folder is over 15g! But there are literally thousands of tiny files in there and a handful of large files. Can I delete all of them and take a fresh backup of my mobile devices?
The Library/Application Support/MobileSync/Backup is where iPhone/iPad/iPod Touch backups get stored. Yes you can delete them, but as soon as you make a new iPhone backup, there is a good chance it will fill backup again. 15GB is not that much, if you iPhone/iPad/iPod Touch has 32, 64, or 128GB themselves.
You might do some experiments. Delete the MobileSync storage. Then backup your iPhone/iPad/iPod Touch and see how much space is taken up. If it is again 15GB, then you might consider starting to move files to an external storage, assuming you want to have backups of your iOS devices. This can get to be a mess. Or look to moving some of the 40GB of music and pictures to an external device. iTunes and iPhoto allow you to specify where the music and photo libraries exist, so you could move them and then tell the apps the new location. I'm sure there is a web page or a dozen web pages that explain how to do this kind of music and photo move.