That folder is located here: ~/Library/Application Support/MobileSync/Backupĭepending on how big your device is, and how often you back up, these backup files can take up tens of gigabytes. One such place that can take up a lot of space is the folder where iTunes saves backups of your iPhone or iPad. The Downloads is one of them, and a lot of people fill it up and forget to empty it, but files are hiding in places you wouldn’t expect. Most of your files will only be in a couple of folders.