iOS 15.7 Update Failed

To update over the air from the phone all of these requirements must be met:

• You need at least 6 GB of free storage
• You must be connected to a Wi-Fi network (and not a personal hotspot) unless it is an iPhone 12 or 13 series or an SE 3rd edition with an active 5G network connection
• The phone must be charged to at least 50%, and preferably plugged in so it stays above 50% during the update
• The phone must not be in Low Power Mode
• The phone must not be connected through VPN, and it may be necessary to delete any VPN apps and VPN profiles
• The phone cannot be in Airplane mode
• You cannot still have a beta version installed on the phone
• You cannot have a previous version that was downloaded, but not installed - go to Settings/General/iPhone Storage to look; if you find an iOS installer, delete it

If you can't meet all of them you can still update using your computer.

Despite some saying 5, 6, 7 GB free I freed up 10GB and had success. 15.7 seems to do a poor job of reporting the reason for the error when it does its memory check. Apple used to "just work", but now that seems to be less of a thing and seems more so every day!!!

What are your symptoms? What is the specific message when it fails? Have you checked all of these?

To update over the air from the phone all of these requirements must be met:

• You need at least 10 GB of free storage for iOS 16 or 6 GB for iOS 15 or lower; more is better
• You must be connected to a Wi-Fi network (and not a personal hotspot) unless it is an iPhone that supports cellular 5G (12, 13, 14 or SE 3rd edition) and has a 5G network connection
• The phone must be charged to at least 50%, and preferably plugged in so it stays above 50% during the update
• The phone must not be in Low Power Mode
• The phone must not be connected through VPN, and it may be necessary to delete any VPN apps and VPN profiles
• The phone cannot be in Airplane mode and must have a cellular data connection
• You cannot still have a beta version installed on the phone
• You cannot have a previous version that was downloaded, but not installed - go to Settings/General/iPhone Storage to look; if you find an iOS installer, delete it

If you can't meet all of them you can still update using your computer.

May conclude that most probably is due to insufficient Storage.

Some say the 5GB, 6GB or 7GB required for the update to be installed successfully.

For my case, 8GB got failure too! At the end, succeeded with 10GB++ free storage😅🤷🏻‍♂️

My guess the issue might be either

1. v15.7’s storage requirement is case by case, or
2. iPhone Storage inaccurate info

Well, why doesn't Apple tell us this? Why do we have to look and look and look on the Internets - until we finally come upon the correct forum - and then read through replies to find someone who supposedly knows what he or she is talking about - to finally understand why the 19 attempts at updating to 15.7 I've made have all FAILED??

Thanks, Apple. I guess with 2 trillion in profits, it's hard to get this kind of information out to your dedicated purchasers.

With this new, hard to find information, I was forced to clear out over 10GB of data from my iPhone 12 - wouldn't work with SIX GIGABYTES of free storage space on it! So, after the 20th update failure, had to offload tons more music to get over TEN GIGABYTES of free space on my phone. THEN it worked.

Again, thanks, Apple.

OMG, thank you! This was so irritating. I had just under 7GBs free for storage but once I cleared up some space it finally worked.

Check how much storage you have left. If you don't have 5-10Gb free, try clearing some of that up, perhaps by offloading it to cloud and then re-running the update.

Now sorted but it required 12GB plus free storage space to work. Now upgrading to IOS 16.

You need to free up space in your internal storage probably at least 12 GB. Also as advised above delete any failed updates.

No, you don't have to upgrade your phone (at least I don't think so). What you should do if there is no other way to delete this kind of baggage, then you can always get rid of it by rebuilding your phone. Make sure you have backed everything up, then completely erase your phone, which will install a clean install of the latest version your phone supports. You will be asked whether to restore your data and you should select yes. I've done this in exactly your situation on and iPhone 6 & 7, as well as my Watch with good results. Lots of articles and videos here and elsewhere. When you are done, you should have a clean install with all your data and apps restored, but you should find this failed update you seem to have has not been restored and then should be able to proceed. BTW, I fixed my problem, but I had to have 10Gb free before it worked for me on and SE Gen 3.

Thanks for the explanation!

And just to be clear, the available storage requirement is for over-the-air updates. Updating using a computer requires much less storage on the phone. The reason is that an OTA update downloads an installer app, not just the update. The installer must run to FIRST install the new version, then switch to it, then delete the old version, and finally delete the installer itself. It works in this order so if the new version fails to install the old version is still present as a fallback. So the update needs over 3 times the size of a finished iOS version to run entirely on the phone: The size of the old version + the size of the new version + the installer itself + the install image in the installer. So 3 iOS images plus the installer.

Installing using a computer the installer remains on the computer, so the storage needed on the phone is just enough to hold the new version and the old version, and after the installation the old version is removed. It doesn’t need the installer or the installation image.

vtskier27 wrote:

The update in only 379.3 mb. How much free space is needed on my iPhone 12? In a previous post it said 6gb is needed. That’s crazy! Amy suggestions. Thanks

1. The update INSTALLER is only 379.3MB. However, to install that update the installer makes a complete copy of the current iOS version, then uncompresses the update, applies the update to the copy it has made, verifies the copy, then deletes the current iOS version and replaces it with the updated iOS version. It does it this way so if the update doesn’t “take” correctly the iPhone still has a working version of iOS that it can fall back to. So it needs enough free storage to hold 2 full copies of iOS during the update process.

Are you trying to download the update onto your computer, or are you updating, using Wi-Fi?

Any error message given?

Due to the increased traffic on Apple Servers, you might get a network error message, related to the slow download speed.

free up 5GB storage, this will solve it.

I updated my phone on ios 16 instead . And yeah you need to free all available storage to get the update! Thanks!!