iPhone 17 Pro brightness drops to 0 after unlocking on iOS 27

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iPhone 17 Pro brightness drops to 0 after unlocking on iOS 27

Hey! 👋🏻

My issue is that since the iOS 27 update let’s say 6 out of 10 times my brightness slider drops to 0 after I unlock my phone. The issue doesn’t appear on the lock screen just after Face ID or passcode unlock. It’s an iPhone 17 pro and I’m running the latest 27.0 software. I’ve tried turning off auto brightness and white point settings. I have no focus mode turned on neither zoom. I’ve tried changing the wallpaper and turning off all the lock screen widgets because among other things that’s what the AI assistant advised.

iPhone 17 Pro, iOS 27

Posted on Sep 26, 2026 9:23 AM

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Answer 1

Top-ranking reply

SravanKrA

Level 10

451,192 points

Sep 26, 2026 9:56 AM in response to Dreadam

This is probably the most important thing to check out. A Personal Automation can adjust screen brightness without needing Focus mode to be on.

Head over to: Shortcuts → Automation

Search for any automation that includes:

Time of Day
Arrive/Leave
When the App is Opened/Closed
Sleep
Charger
Focus

Any action that involves Set Brightness

If you spot one, try turning it off for a bit.

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Answer 2

Oct 18, 2026 3:08 AM in response to RrraaaarrrMe

Hi, I don’t have the issue currently on my iPhone 17 PM. An update to iOS 26 resolved it and the device is on 27.0.1 and no issue. I know it’s not a fix but a simple and easy way to quickly resume use is to just say “Siri, set brightness to 75%” and instantly the screen is usable.

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Answer 3

SravanKrA

Level 10

451,192 points

Sep 26, 2026 9:54 AM in response to Dreadam

Dreadam wrote:

...since the iOS 27 update

Not every issue an individual encounters on their device can be attributed to an iOS update. If the update itself were the root cause, then every device running that same version of iOS would exhibit the identical problem. In such a scenario, the forums would be flooded with countless posts reporting the same malfunction, creating an unmistakable wave of complaints that no one could possibly overlook. The absence of such widespread reports strongly indicates that the issue is not systemic, but rather specific to the device in question.

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Answer 4

Dreadam Author

Level 1

5 points

Sep 26, 2026 10:14 AM in response to SravanKrA

It’s probably not connected to the iOS update as you said I just thought it’s worth mentioning for full context.

On the topic of automations , I don’t have any automations running on my device. I have a shortcuts in form of a tool menu but it’s not in automation.

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Answer 5

Dreadam Author

Level 1

5 points

Oct 6, 2026 2:35 PM in response to Dreadam

The issue still hasn’t been resolved, I tried hard reset, recalibrating the light sensor, even removed and later changed the screen protector, non of them have worked. I’m starting to suspect it’s a hardware issue but I don’t have coverage and don’t really feel like spending hundreds on a repair however annoying this might be. It’s frustrating tho for sure because it always dims the screen when I actually need the phone for work.

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Answer 6

Oct 17, 2026 10:08 PM in response to Dreadam

I’m facing the same exact issue. I have no automations set. This started after IOS 27.0.1 . With this I’m also facing an extremely laggy phone app which barely loads contacts. Tried restarting Multiple times.

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