Slow performance and lag after iOS 26 update on iPhone

I've been having the same issues as everyone else. After two hours on the phone with both regular support and senior advisors, we got nowhere. But my problems go beyond just lag and overheating. My calendar was completely wiped clean, the widget stopped showing appointments, and I couldn't even permanently delete files—they'd get stuck in the "recently deleted" folder. To top it off, iMessage would show "failed to send" even when the other person received the text.

The most frustrating part? The senior advisors were just as confused as I was. Their final advice was to just keep installing future updates and "hope" one fixes it.

My iPhone is getting a very bad sound lag. Ever since updating it’s been affected heavily. There was a sound lag for keyboard - when it sometimes disappears while typing and sometimes grows very loud - before, but now it’s across the entire system. Alarms now behave weird and my reminder at first vibrated and then had a sound with a 9 minute delay (it’s also not set to vibrate). Silence toggle reacts with a small delay like never before.

Screen locking sound behaves very strange and repeats itself.

Yes, also on my old 12 unlocking screen takes a longer moment and it shows darkened wallpaper but that’s because of the lack of Dynamic Island that shows Face ID icon.

At first there was lag for both my current and old iPhones but now it’s kinda most noticeable on my current iPhone since I use it most and have it not silenced. I hope next update fixes a lot of things and it gets more stable over time since it’s already been a while since the update and this kind of issue usually doesn’t happen to my iPhones

I have the same problem today after updating my iPad A16 from iPadOS 18 to 26.

In my case (iPad A16 & iPadOS 26), that's enough for fixing. I tested with 3D game Critical Strike, lag issue has gone.

But if the problem is still not resolved, try again after a few days to let the OS finish processing background tasks.

Good luck

https://www.youtube.com/watch?v=k6zwVuDJ9cw

Perhaps a long shot:

Do you have a 3rd party VPN installed, even if you are not using it? If so, delete the VPN profile in Settings/General/VPN & Device Management/VPN, then restart your device. Don't just turn it off; delete the profile. If that fixes it, you can try reinstalling VPN, but probably shouldn't.

(VPN isn’t the cause of all problems, but it is responsible for a great many)

Good Morning everyone!

Another one here.

iPhone 14 256GB - 70GB free space

Battery capacity 87%

iOS 26.0.1

Imediately after upgrading to iOS26 seven days ago I faced performance issues, which I don’t have on any other, even older devices.

Clear indicator is the Home Assistant app (or calling Home Assistant in Safari or Chrome), which has terrible lags. Also this - not occurring on devices with iOS18 in the same environment.

I am really a fan, but what Apple is presenting here is just sad. Instead of sketching new icons, they should invest some time in integration testing.

The latest patch iOS 26.0.1 has partially solved the problem for my iPhone 12. Now the APPs don't crash, and the phone has minimized the absolutely laggy behaviour of iOS 26. Still lags, but at least the phone can be used.

Folks, I think I figured it out. TURN OFF LOW POWER MODE

mainly I was experiencing micro lag. I’ve done everything from reduce transparency, update all apps, turn on and off phone - but the solve was to turn off low power mode.

hope this helps

Mac/Jim, you seem to be pretty well plugged in. This thread is swarming with really bad 26 bugs.

I have a healthy 15ProMax running 17.5 because that's the most recent ios my freestyle glucose monitor app is compatible with. But I'll soon be switching to Dexcom7 monitors, which claim compatibility with ios 26. If I can upgrade that would be great.

But this thread is really alarming. Are engineers working on the lag/battery/other issues and will apprpriate patches be available soon? If not, updating is too risky and doesn't seem worth it.

Edit: Thought this was going to drop under Userkoozer’s response to toggle reduce transparency.

This should be one the top comments. I had to do this on my 4th Gen iPad. It didn’t completely resolve the issue because there is still a slight stutter when swiping between my list of apps. However, it does help a lot! Can confirm, it helped my iPhone 15 Pro max as well!

Not sure if anyone has seen slowness with the camera app. It seems pretty sluggish swiping between camera to video, etc. even with reduced transparency.

Thanks OP for posting this issue, thought I was going crazy!

You have a lag problem on your phone. Millions of users with iOS 26 do not have a lag problem, or they would tell us. So you need to troubleshoot the problem, or contact Apple support for help.

• Reading the rest of this thread would be a good starting point.
• If you have any apps to “improve” the performance or management of your iPhone, get rid of them.
• If you have an antivirus or similar app get rid of it.
• If you have VPN installed delete the VPN profile, don’t just turn it off or delete the app; it’s the profile that has to go

This was exactly it. The transparency setting is causing functional lag even in higher processing devices. It’s a bug not a feature.

While toggling helped it didn’t eliminate lag in say the search/text pop up but leaving it off does.

you found the culprit.

Same issues, 1TB 15 Pro.. iOS 26.0.1, running caseless 24/7.

What fixed it for me is to completely turn off Apple Intelligence. Phone doesn’t get near as hot and doesn’t suffer through thermal throttling issues anymore. Up until that I was experiencing severe lag and then thermal throttling when charging and also when connected to wired CarPlay. No VPN profiles, more than 50% left in storage. Tried turning on reduce transparency, slightly helped. Try turning off Apple Intelligence.

Have you contacted Apple Support. If not why? This is not Apple Support and Apple and Apple Support do not participate here. Everyone commenting and posting are fellow Apple users just like you.

If you’re in the US please call  1-800-MY-APPLE or outside the US, consult the support articles below. In Canada call 1-800-263-3394

Contact Apple for support and service - Apple Support

Genius Bar Reservation and Apple Support Options - Apple

shianne277 wrote:

A few days? But after updating mine it’s still being slow and laggy for like a month now and I jsut updated it to the iOS 26.01 and it’s still so slow and laggy and kicking me off apps

Check your battery health at Settings > Battery > Battery Health > Maximum Capacity. If it is below 80%, then you will need your battery replaced, and that would have been true on iOS 18 as well. You may be experiencing increased demands on a battery that is not capable of providing the power and there may also be a message under Peak Performance Capability that also says that the performance is being limited.

iPhone battery and performance - Apple Support

I have an iPhone 15 Pro. I tried reducing Transparency in Accessibility. I tried removing my VPN profile. These did not work.

What worked was turning off Apple Intelligence. As soon as I turned it off my phone lag was gone.

Hope this works for you.