iOS 27 has been available since September 14, and while many iPhone owners report smoother performance than iOS 26, others are running into bugs ranging from battery drain and keyboard lag to cellular failures, Home Screen glitches, broken auto-brightness, and unexpected restarts on the new iPhone 18 Pro models.
Apple has already confirmed that a software update is coming to address one of the more serious problems involving Face ID and unexpected restarts on the iPhone 18 Pro and iPhone 18 Pro Max. iOS 27.0.1 is currently being tested and is expected to become the first bug-fix update for iOS 27.
If you have just installed the update, you can also check our complete iOS 27 release coverage and iOS 27 features roundup before troubleshooting.
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iOS 27 bugs reported so far
Reports across r/iOS, r/iOS27, r/iPhone, r/iPhone18Pro, r/iPhone15Pro, Apple’s Support Community, and other forums point to the following problems.
| Reported iOS 27 issue | Where users are reporting it | Suggested fix or workaround |
|---|---|---|
| Battery draining quickly | r/iOS27, Apple Support Community | Wait several days for indexing, restart, check Settings > Battery |
| iPhone running hot | r/iOS27 | Allow post-update processing to finish and check battery activity |
| Face ID failures and restarts | r/iPhone18Pro, r/iPhone | Reset Face ID and install Apple’s upcoming update |
| Random restarts | r/iPhone18Pro, Apple Support Community | Force restart and check panic logs if it continues |
| Keyboard lag | r/iOS, r/iPhone | Restart and temporarily disable keyboard haptics |
| Home Screen stuttering | r/iOS27 | Switch from tinted or clear icons to default icons |
| Blank Home Screen folders | r/iOS | Restart the iPhone |
| Auto-brightness behaving incorrectly | r/iOS27, r/iPhone15Pro | Toggle auto-brightness or restart |
| Apps freezing or showing black screens | r/iOS | Force-close, update, or reinstall affected apps |
| Cellular connection problems | Apple Support Community | Toggle Airplane Mode, restart, contact carrier |
| CarPlay glitches | r/iOS27, Apple Support Community | Forget and reconnect the vehicle |
| RCS/SMS Continuity problems | r/iOS27 | Restart connected Apple devices and re-enable forwarding |
| App Library problems | r/iOS27 | Restart or temporarily disable visual customization |
| Calendar and widget glitches | r/iOS, social media | Remove and re-add the widget |
| Dynamic Island visual glitches | r/iOS27 | Restart the iPhone |
| Focus modes not ending on schedule | r/iOS | Disable and recreate the Focus schedule |
| Ringer volume unexpectedly changing | r/iOS | Restart and check Sounds & Haptics settings |
| Screen taps failing to register | r/iOS27 | Restart and disable tinted icons |
| Camera interface orientation glitches | r/iOS27 | Close Camera and restart |
| App deletion option missing | Apple Support Community | Check Screen Time restrictions |
These reports do not mean every iPhone running iOS 27 has the same problems. Several users in the same discussions say iOS 27 is running normally or significantly better than iOS 26 on their devices.
Battery drain and overheating
Battery drain remains one of the most common complaints after the iOS 27 update. An Apple Support Community thread includes an iPhone 17 Pro owner reporting unusually high battery usage after installing the update, while Reddit users have reported similar behavior on the iPhone 15 Pro Max and other models.
However, high battery usage immediately after a major update does not always indicate a bug.
Apple says background tasks continue after installation, including indexing files and completing device setup. The Battery page can show an “Ongoing iOS Update” notice while this work continues, and Apple recommends waiting several days before judging battery life.
Try these steps:
- Open Settings > Battery and check which apps or system processes are using the most power.
- Restart the iPhone after indexing has finished.
- Update all apps through the App Store.
- Wait several days after installing iOS 27 before comparing battery life.
- Use Adaptive Power if your iPhone supports it.
Persistent overheating while the phone is idle deserves more attention, especially after the initial indexing period ends.
Face ID can crash some iPhone 18 Pro models
The most significant confirmed iOS 27 problem currently affects some iPhone 18 Pro and iPhone 18 Pro Max units.
Users in r/iPhone18Pro describe situations where Face ID fails while authenticating an app, after which the phone freezes and restarts. Similar reports mention panic logs after repeated crashes.
Apple has confirmed that it plans to release a software update to address the problem. The company has not formally named the update, although iOS 27.0.1 is already appearing in testing data.
Until that update arrives, try resetting Face ID:
- Open Settings.
- Go to Face ID & Passcode.
- Tap Reset Face ID.
- Restart the iPhone.
- Set up Face ID again.
Apple documents Face ID setup and reset controls inside the same settings page.
Keyboard lag and delayed typing
Several r/iOS users say the stock keyboard feels slower after installing iOS 27, particularly in Messages. Reports describe delayed key animations, slow haptic feedback, missed input, and occasional incorrect space-bar presses.
There is no confirmed system-wide fix yet. Restarting the phone is the simplest first step, while some users report improvement after disabling Keyboard Feedback under:
Settings > Sounds & Haptics > Keyboard Feedback
You can also test with haptics and sound disabled to determine whether the slowdown relates to keyboard feedback.
Home Screen, Liquid Glass and icon glitches
Home Screen customization appears to trigger several graphical problems.
An r/iOS27 discussion reports stuttering when tinted or transparent icons are enabled, while another user says changing back to standard icons noticeably reduced interface jitter.
Other reported visual bugs include:
- Folders appearing blank until opened.
- Icons flashing black while unlocking.
- App Library visual glitches.
- Settings icons failing to load.
- Landscape animations behaving incorrectly.
- Dynamic Island expanding incorrectly.
- Calendar widgets flickering or temporarily showing no events.
- Tinted icons remaining active after the setting has been disabled.
Apple introduced additional Liquid Glass customization in iOS 27, which you can read about in our iOS 27 interface changes overview.
For now, switching to standard app icons, removing the affected widget, and restarting the device appear to be the most practical workarounds.
Auto-brightness problems
Some iPhone 15 Pro owners say auto-brightness became unreliable after moving to iOS 27, with displays staying too dim outdoors or becoming excessively bright in dark rooms.
The issue appears in both r/iPhone15Pro and r/iOS27 discussions. Some users report that brightness remains unusually low even when the slider is increased.
Try turning Auto-Brightness off and back on under:
Settings > Accessibility > Display & Text Size > Auto-Brightness
A restart has also temporarily restored normal brightness for some users.
Cellular, AT&T and eSIM problems
Cellular connectivity is another repeated complaint.
An Apple Support Community thread contains reports from iPhone 14 Pro, iPhone 15 Plus, iPhone 17, and iPhone 18 Pro Max users who experienced unreliable mobile data or could no longer place calls after installing iOS 27. Some reports involve AT&T, although the problem does not appear limited to one model.
For cellular problems, Apple recommends:
- Turn Airplane Mode on for at least 15 seconds, then turn it off.
- Restart the iPhone.
- Check for carrier settings updates.
- Contact your carrier and confirm the account and eSIM are correctly provisioned.
If Wi-Fi is also affected, Settings > General > Transfer or Reset iPhone > Reset > Reset Network Settings can clear damaged network configuration, although this removes saved Wi-Fi passwords, VPN settings, and other network preferences.
CarPlay and connectivity glitches
Some users also report CarPlay problems, including broken media controls, connection instability, and calling or messaging problems while connected to a vehicle.
Apple recommends restarting both the car and iPhone, checking Wi-Fi and Bluetooth for wireless CarPlay, and then going to:
Settings > General > CarPlay > [Your Car] > Forget This Car
Reconnect the vehicle afterward.
Apps freezing, crashing or turning black
Users in r/iOS have reported applications hanging or opening to a black screen after updating, while other discussions mention Calendar crashes and video playback glitches.
For an affected app:
- Force-close it and reopen it.
- Restart your iPhone.
- Install any available App Store update.
- Delete and reinstall the app if the issue remains.
Apple recommends the same troubleshooting order for apps that stop responding or close unexpectedly.
Should you wait for iOS 27.0.1?
Apple released iOS 27 on September 14 for the iPhone 11 and newer models, along with the second-generation iPhone SE and later.
As of September 28, Apple has not publicly released iOS 27.0.1, but it has confirmed that an update addressing the iPhone 18 Pro Face ID restart problem is coming.
If iOS 27 is already running normally on your iPhone, there is no need to change anything. If you are experiencing one of the problems above, restart the device, install all available app updates, and check Settings > General > Software Update regularly.
For broader coverage of the release, see our iOS 27 launch guide and complete list of iOS 27 changes.
Apple is likely to address additional launch bugs through upcoming iOS 27 updates, although it has not confirmed which of the community-reported issues besides the iPhone 18 Pro Face ID problem are currently scheduled for fixes.
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