A trick to get more storage space on your iPhone has been circulating online for a few days now – but you need to have less than a gigabyte of available space on your phone for it to work.
Reddit user eavesdroppingyou posted a tactic to clear up extra space that involves renting a movie from iTunes (don't worry, you won't be charged). eavesdroppingyou suggests choosing a large movie, like The Lord of the Rings: The Two Towers , because the trick requires the movie's file size to exceed the amount of storage available on your phone.
After you press the Rent button on a movie, a dialog box will appear, asking you to press OK or Settings. Select Settings.
Your phone will take you to the Settings menu. If you take a look at General –> Storage & iCloud Usage, you’ll see that your phone’s available storage space has probably increased. The iPhone 5S I used with iOS 9.3 started with 890MB and went up to 1.6GB available.
If you press the button to go to the home screen, you can see your iPhone working on different apps, graying them out and replacing their names with “Clearing…”. This probably means your phone is removing some unused data and things like cookies, caches, and history. Your iPhone might do this automatically when storage is very low, but this is a great way to force the process to happen an hour earlier.
During my testing, my phone started from Safari, and it also cleared the Twitter, Snapchat, and Imgur apps.
The Reddit suggested renting the movie multiple times to free up more space, and it does work. After three cleanups in a row, my iPhone had 3.9GB of available storage, and I hadn't removed any apps, photos, or podcasts.
Try forcing your phone to do the cleaning for you yourself – it could save you from deleting some stuff you'd probably rather not give up!
