I realized yesterday that I had no disk space left on my iPhone 5 after I got spammed with iOS notifications that my apps could not be updated (due to lack of disk space). This morning I woke up to about 350 MB of free space - and I didn't do anything.

I don't know what the exact numbers were for usage (Settings --> General --> Storage & iCloud Usage --> Manage Storage), so I don't know what happened. As well as gaining free space, about 10 apps were updated.

My best guess is that there is some internal routine to compress images, since at full resolution they take up a fair amount of space, but even minimal lossy compression can save megabytes per photo without a noticeable loss in quality.

Is there such a documented process, or did something else happen? In any case, I wish I would have screenshotted the storage usage before this happened...

  • The system does automatically free up space when low, like deleting caches.
    – Harcker
    Commented Mar 20, 2017 at 14:50
  • It's not just apps it's also iCloud data. Did you do anything with iCloud on any devices signed-in with the same Apple ID recently?
    – fsb
    Commented Mar 20, 2017 at 19:17
  • @fsb Nope, this happened overnight with no action on my part. Commented Mar 20, 2017 at 22:39

5 Answers 5


You can try to do the most obvious and smart things that free up space on your iPhone. Which are

  1. Upgrade to iOS 10.3: Apple’s new file system, Apple File System (APFS) included in iOS 10.3 is optimized for flash and solid-state drive storage. According to [Apple Insider][1], there has been a gain of space of almost 8GB in a 256GB model. But don’t expect a gain of 6-8GB in your 16GB or 32GB. As Apple Insider explains, the more memory you have, the more free space iOS 10.3 will reclaim.

  2. Backup Photos using Google Photos: Google Photos is basically a cloud storage for your photos. It works great with iOS too. Google Photos offers unlimited photos and videos for free, up to 16 megapixels and 1080p HD. Photos that are safely backed up can be removed from your device’s storage in just a tap.

  3. Remove “Other” Data on your phone: When you connect your iPhone to a computer and open iTunes, you would encounter the “Other” section in little iTunes usage bar graph. Check out this tip by OSXdaily on how to manage this issue. http://osxdaily.com/2013/07/24/remove-other-data-storage-iphone-ipad/

  4. Use Progressive Web Apps (PWA): Although PWA offers to free up app space, iOS doesn’t fully support it at this point. Some features such as Add to Home Screen and Push Notifications, are available in some form in Safari but are not implemented in standard ways. To give you a comparison of the Space utilization for an App VS PWA, the Twitter app has a size of 196 MB in the app store. But the PWA app for twitter is just 1-2MB!

  5. Stream your music instead of downloading them

  6. Remove offline reading list data in Safari: This can be done by navigating to Settings and then General > Usage > Manage Storage > Safari. Then, go to Offline Reading List and tap Delete.

  7. Clear the Safari browser cache: To clean up the cache, simply go to Settings > Safari > Clear History and Website Data.

  8. Remove items from iBooks

  9. Disable using My Photo Stream: Go to Settings > iCloud > Photos, then turn off My Photo Stream

  10. Delete Burst Mode photos

  11. Don’t keep both photos when you enable HDR mode. Go to Settings > Photos & Camera, then deselect Keep Normal Photo

If you have tried most of the above-mentioned tips and still find yourself with less storage space then follow this trick to gain more space. This trick forces iOS to clear it OS cache. There has been an ongoing argument that since this is a system level cache it would have been freed anyway when you actually needed the space. But this does not seem to work if you are in the middle of taking a video and run our of space. http://techathlon.com/free-gbs-space-iphone-deleting-photos-apps-files/.

  • 1
    Welcome to Ask Different, and thanks a lot for your elaborate and helpful contribution. One possible improvement to your answer would be to add one sentence or two to summarize the methods the external links provide, and to add them to your answer, e. g. in quoted form. The thing is that ideally, Stack Exchange answers are supposed to stand for themselves even in the face of link rot.
    – Synoli
    Commented Apr 18, 2017 at 15:46

What I would do:

  1. Plug your iPhone into your computer and use iTunes to back it up locally.
  2. Unplug your iPhone and go into Settings > General > reset > erase all content and settings, wipe the phone. it will take 5-10 minutes.
  3. Once you have wiped your phone, plug it back in to your computer and use iTunes to restore from the backup you just made.

(yes backing up and then restoring your iPhone frees up space)

It is likely that you will have regained at least a bit of free space, allowing you to do what you need to do to to delete apps, emails, photos, music, etc. and free up some space.

  • 2
    Agree that restore will help OP free up space but question was about how space became free without user intervention, not how to free up space.
    – JBallin
    Commented Mar 21, 2017 at 21:28

You most likely have your iPhone set up to optimize photo and/or music storage.

Settings > Photos & Camera see if Optimize iPhone Storage is selected.

If your iPhone is low on space, full-resolution photos and videos are automatically replaced with optimized versions. Full-resolution versions are stored in iCloud.

Settings > Music > Downloads and see if Optimize Storage is on.

If your iPhone is low on space, automatically remove music from this iPhone that you haven't played in a while.

  • Interesting, my iOS version is up-to-date (as of yesterday), but I don't see the Optimize iPhone Storage setting. Commented Mar 21, 2017 at 21:44
  • Do you have iCloud photo library on? Wouldn't be there if not. Did you check Music? I suppose you would need to be an Apple Music subscriber.
    – JBallin
    Commented Mar 21, 2017 at 21:55
  • Nope! But I just turned it on and now see the setting. But, given that it was originally off, this can't possibly be the reason for random extra disk space gained :) Thank you for your answer though, this could likely explain why this happens to other people! Commented Mar 22, 2017 at 2:23

Possibly one of your apps is refreshing in the background and loading content. For example I believe Snapchat is able to do this, imagine that your friends posted a bunch of content and then it expired over night. Some video services that allow offline downloads can also expire.

The content requires storage but storage will be reduced once it's gone.

Diagnosis: Take screen shots of your storage usage by app with 24 hour gaps to see if some of them fluctuate and by how much.

  • Answers on StackExchange are not typical 'forum' posts, you should really make this a comment on your existing answer. Answers are here to answer the question posted, and comments (on the question, or on other answers) are for discussion of the Q/A :) Commented Mar 22, 2017 at 2:55
  • I thought this would be cleanest as it's a separate idea. If I were to solve your problem in the comments and you marked my solution as the answer than people may not read comments in the future (wrong answer would be marked correct). Alternatively if I over-wrote my answer it wouldn't help others who, as you said, are likely to solve this issue with the solutions presented in that answer. Let me know if my logic is wrong, thanks!
    – JBallin
    Commented Mar 22, 2017 at 2:58
  • Very good point, I wasn't sure if you were aware of 'SE is not a forum'. In any case, I couldn't possibly pinpoint if an app took up several hundred megabytes of space only to suddenly not require that space, without examining it over the long term. However, I will continue to monitor my disk usage and see if anything happens. I may also go ahead and fill up the rest of the space manually by downloading some Spotify songs just to see if this happens again. I'll keep you posted! Commented Mar 22, 2017 at 3:04
  • True. Updated with a better diagnostic solution.
    – JBallin
    Commented Mar 22, 2017 at 5:34

I will go with what chris said and i won't do what steve said if the phone is not giving you any problems i would suggest to go to apple store and download any app which will help to clean your cache and temporary files. I know you don't have free space to download it probebly but it us better to have it and use it time to time to get some free space. You shouldn't worry about getting free space automatically cause the phone won't delete anything that is important by it-self it only deletes or upload files to iCloud if you have enabled the photo stream or sharing cause after uploading to icloud it deletes the pics from your phone that maybe gave you some space.

  • Apple has said that users don't need apps that 'free-up space' because they don't really do that on the iPhone (iOS will do that automatically). What @steve-chambers said to do is accurate and proven to free-up space; in fact, Apple has said to do that, also. Your answer doesn't make much sense and shouldn't be followed.
    – fsb
    Commented Mar 21, 2017 at 12:52

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