I started using iCloud Photos recently and love it. I have photos syncing on my iPhone(16gb), my MacBook Pro(240gb), and in the cloud of course.

My issue is that I have 12 photos on my phone that are not syncing to the cloud. I am on WiFi, the phone is fully charged, and they are just stuck on my phone. I've looked on my MBP and they aren't there. I've looked on the iCloud via the web app and they aren't there.

When I go on my phone to iCloud / Photos, the message says "Low Disk Space - Uploading 12 Photos" I have 163mb of free space on my phone, and 125gb of free space in iCloud.

My Question is, is there a way that I can manually clear the cache of photos that have downloaded to my phone. I have 750mb used in the "Photos & Camera" application, and I am sure a good chunk of that is from me browsing old photos which are temporarily downloaded to the phone for viewing. When I typically look at my library on my phone, the photos start off as empty white squares and that's okay. I've looked at a bunch, and it downloads thumbnails and lower res images of the files. Can I clear these caches to free up some space?

Also, I've read that the system requires at least 300mb of free space on your phone to upload photos to the cloud. Is this true? I can't see why this would be a requirement.

3 Answers 3


Apple doesn't list a required/minimum free space, so you'd need to work with Apple support to get that sorted. As for the cache, you've already done all you can.

iOS has several low storage warnings it sends to each and every app to clean up cached files and with < 500 MB of free space, I'd wager you've exercised those limits continuously and it's surprising to me if this is the only thing that is broken on your device right now.

I would:

  1. Delete one or two large apps that you know the data is safe/unimportant. Try to get 2 GB of free space if you can but 1 GB of free storage should be sufficient.
  2. Power off the device and power it on to let system cache files re-generate
  3. Open photos on the device and on iCloud and see if normal operations resume. I've had good luck with photo libraries coming back from all sorts of intentional abuse like you've unintentionally performed. It can take 24 hours or more (if you hit any upload limits) for the cleanup script(s) to trigger so you might wait 48 hours to see if the added space lets iOS complete the upload work that is queued.

Also, Apple does offer debugging profiles for iOS cloud sync if you call in for support and if their "cookbook" method doesn't yield results. If your case get escalated to engineering specific error messages contained in the debug logs can often assist you in further diagnosing why all the photos are not syncing.

You could also just push the photos to a computer or other iOS device using AirDrop or USB and upload them to the cloud from another device and then remove iCloud Photos temporarily from your iPhone to allow enough space to resume normal operations and then re-enable the library with the option to reduce file size.

Basically, the system is designed to stop working when there isn't enough space for temporary files to work. This is the same design as OS X and other unix in general.

These operating systems use free storage space to cache things and make your experience better by accelerating slow resources like network and CPU by saving work when it's done to reuse it later. When you deprive the system of that buffer, things slow and eventually stop.

  • 1
    I have removed all 3gb of my music from my phone (it's still on my MBP). I then restarted the iPhone. Now the message in Settings / iCloud / Photos, reads "# Photos to Upload". I have the iCloud web app open and I am starting to see them in iCloud Photos. Thank you. :) This is strange, and it makes me wonder if the 300mb minimum free space is a true thing...
    – Frantumn
    Commented Jan 18, 2016 at 14:50

The "one weird trick" that works regularly for me is to attempt to rent a large movie in iTunes. Go find a movie that you know won't fit on your phone. Before actually charging you for the movie iTunes will attempt to free up enough disk space to download it.

You can actually try this several times. Some times it doesn't work at all, but often times it will free up a few hundred MB and then you can immediately try again and free up a few hundred more. Each time iTunes will fail to rent the movie due to low disk space, but it will still have cleared a lot of cache in the process.

  • 1
    I just tried this and it freed up about 900mb... thanks for the tip! I wish Apple would provide a button for this in the settings though...
    – brendan
    Commented Jan 2, 2018 at 22:58
  • Oh my god thanks so much! I'm always filling my devices despite always buying the largest model Apple makes, and so I'm constantly experiencing major issues and repeated corruption due to low disk space. Oddly my iPhone 5 running iOS 9 hardly ever had a problem despite filling it to 0 bytes on a frequent basis, but my iPad Pro on iOS 10.2.1 begins corrupting my Photos.sqlite DB which makes my entire Photos app go blank and then when I able to recover it with a lot of work, it takes days to rebuild and I've still lost recent albums and recent changes. So this will be a very helpful trick. Commented Aug 2, 2018 at 7:05

Go to youtube, search "One Weird Trick to Free Up Storage Space on iPhone", site under iTwe4kz. I searched for a while and finally found the solution in this guy's youtube channel, published Mar 28, 2016.

  • 2
    In addition to your source, please include content (i.e. explain what the YouTube video says)
    – brickery
    Commented May 21, 2016 at 3:55

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