iPhone 16 Problems: Battery, Overheating and iOS 27 Bug Fixes

You go to rearrange a widget and the whole Home Screen crashes back to a black screen. That’s one of the iPhone 16 problems owners started posting about within days of iOS 27, along with faster battery drain, a phone that feels warm in the hand, stuttering animations and a Camera Control button that stops responding the way it used to.

The iPhone 16 is two years old now and sold refurbished almost everywhere, so a lot of people meet these issues on a phone they’ve just bought. Most of them are software or settings. A few aren’t, and those are listed near the end.

What changed with iOS 27 and 27.0.1

The iPhone 16, 16 Plus, 16 Pro and 16 Pro Max all run iOS 27, which Apple released on 14 September 2026. iOS 27.0.1 followed on 28 September 2026. Its release notes list three fixes. Two are for the iPhone 18 Pro models (Face ID restarts and a colour artifact in 2x photos). The third, a touchscreen freeze when Notification Center and Control Center are opened at the same time, applies to every iOS 27 iPhone, the 16 included.

Cybernews collected user reports after launch. Besides that freeze, people described the interface crashing while editing Home Screen widgets, laggy animations in WhatsApp, Reddit and Wallet, battery drain and random restarts. Apple has not acknowledged a battery problem specific to iOS 27.

The update’s effects on other models are covered in our iOS 27 problems page.

Try these three things first

1. Get the latest iOS 27 release from Settings › General › Software Update. Point releases like 27.0.1 often carry stability work that isn’t in the notes.
2. Force restart. Press and release volume up, press and release volume down, then hold the side button until the Apple logo appears. Stuck processes go; your data stays.
3. Update your apps. In the App Store, tap your profile picture and update everything. A lot of crashes after a big iOS release come from apps that haven’t been rebuilt for it yet.

Battery dropping overnight

The usual complaint is a battery that falls noticeably faster than before the update, sometimes overnight with the phone doing nothing. Some owners also feel the back get warm while it sits on a desk.

After a major update, iOS re-indexes photos, messages and mail for search and refreshes apps in the background. Apple’s support guidance says this can affect battery life and thermal performance for a while. Updates aren’t the only trigger, though. In July 2026 PhoneArena reported a wave of drain and heat complaints after the iOS 26.5.2 security update, one of them from an iPhone 16 Pro Max owner. One app or process stuck in a loop can make any update look bad.

1. Give it two or three nights on a charger, on Wi-Fi, with the screen locked, so indexing can finish.
2. Find the app. Settings › Battery shows usage for the last 24 hours and 10 days. Heavy background activity is the giveaway. Update that app, or delete and reinstall it.
3. Cut Background App Refresh in Settings › General › Background App Refresh for apps that don’t need new content while closed.
4. Check location access in Settings › Privacy & Security › Location Services. Move apps from Always to While Using where you can.
5. Reset All Settings if the drain lasts more than a week: Settings › General › Transfer or Reset iPhone › Reset › Reset All Settings. Data stays. Preferences and Wi-Fi passwords don’t.
6. Try a clean setup. A backup made years ago can carry old settings and glitches with it. Back up, erase, set up as new, and see whether the drain is still there.

Then look at the battery itself in Settings › Battery › Battery Health & Charging. Apple designs iPhone 15 and later batteries to keep about 80% of their original capacity at 1,000 complete charge cycles. Maximum Capacity well under 80%, or a service message, means it needs replacing. Each message is explained in our battery health and parts history guide.

Warm or actually overheating?

Warm is normal for the first day or two after an update, during gaming or navigation, and while fast charging. Overheating looks different: a temperature warning on screen, the display dimming by itself, or charging that keeps pausing.

Indexing, the camera, navigation and games all work the A18 or A18 Pro chip hard, and charging adds heat on top. iOS will also hold charging at 80% when the battery is warm. That’s deliberate, to protect the battery.

• Take a thick case off while charging. Don’t charge under a pillow or in direct sun.
• Use an Apple or certified USB-C charger and cable.
• Close the camera, maps and games when you’re done with them.
• Look in Settings › Battery for one app taking an odd share of power.
• Check Settings › Battery › Charging. Optimized Battery Charging and the 80% limit can make a warm phone look as if it has stopped charging.

Hot while idle, and still hot after a week of trying the above? Ask Apple Support to run diagnostics.

Widget crashes, lag and apps closing

Animations stutter between screens, the keyboard lags, or apps drop you back at the Home Screen. Reddit users quoted by Cybernews said editing Home Screen widgets crashed the entire interface until they restarted.

1. Restart. The widget crash clears with a restart.
2. Thin out the Home Screen. Fewer widgets and apps on it is the workaround TechRadar suggested for the UI lag, as cited by Cybernews.
3. Free storage in Settings › General › iPhone Storage. Keep at least 10% free so iOS can finish its background tasks.
4. Update or reinstall the app that crashes. If it’s only one app, the developer usually has to ship an iOS 27 update.
5. Confirm which app it is in Settings › Privacy & Security › Analytics & Improvements › Analytics Data. The same app name over and over is your answer.
6. Reset All Settings, then try a clean setup if the lag stays.

Camera Control ignores light presses

Camera Control is the capacitive button on the right side of every iPhone 16 model. It can feel dead after an update, with a new case, or when a screen protector overlaps its edge.

1. Take the case off and test. A case needs a precise cut-out or a conductive cover for the light-press and swipe gestures to register.
2. Check Settings › Camera › Camera Control. This is where you pick what it opens and whether a single or double click launches it.
3. Change the sensitivity. Light-press force and double-click speed live under Settings › Accessibility › Camera Control. Try lighter, then firmer.
4. Restart and test again in the Camera app.

If it doesn’t click at all, or only works some of the time without a case and after a restart, the button is faulty. Book an Apple repair while you’re still covered.

Wi-Fi keeps dropping

1. Switch Wi-Fi off in Settings (not Control Center), restart, and switch it back on.
2. Forget and rejoin: Settings › Wi-Fi › ⓘ next to the network › Forget This Network.
3. If your router or a hotel login page rejects the phone, set Private Wi-Fi Address to Fixed or Off for that network.
4. Restart the router and update its firmware.
5. Reset Network Settings in Settings › General › Transfer or Reset iPhone › Reset › Reset Network Settings. Have your Wi-Fi passwords ready.

Wi-Fi that fails on every network, with the toggle greyed out, is hardware.

Signs it needs a repair, and checking cover first

Check coverage before you pay anyone. A free All-in-one Basic Info check confirms the model and basic warranty status from the IMEI or serial. An iPhone warranty check shows whether Apple’s limited warranty or AppleCare still applies. And if you’d rather replace the phone than fix it, our list of iPhones supported by iOS 27 helps you pick one that will keep getting updates.

Checks before you buy a used iPhone 16

On a second-hand iPhone 16, plenty of “problems” come from the phone’s past, not from iOS 27: a non-genuine battery or screen, earlier repairs, or a phone still tied to someone else’s account.

• Open Settings › General › About › Parts and Service History and look for replaced parts.
• Confirm model, colour, storage and Find My status with an Apple model and Find My check.
• Want repair history and replacement-unit records too? A full GSX report goes further.
• Press Camera Control without a case on, and check Battery Health before you pay.