Your iPhone screen stays on and won’t auto-lock. In our testing across iPhone 13, 14, and 15 running iOS 16 through iOS 17, this issue came down to a settings conflict in nearly every case, not a hardware problem.
- Check Settings > Display & Brightness > Auto-Lock first; it may be set to Never
- Low Power Mode overrides Auto-Lock on many iPhones; disable it in Settings > Battery
- AssistiveTouch can prevent the screen from dimming if the floating button stays active
- Exchange Server email profiles can lock Auto-Lock to Never and gray out the option
- Force-restarting clears software glitches that cause Auto-Lock to stop responding
#Why Auto-Lock Stops Working on iPhone
Six causes account for nearly all Auto-Lock failures. Identifying the right one saves time.
Low Power Mode overrides Auto-Lock when the battery drops below 20%. iOS adjusts display behavior to conserve power, which can prevent the screen from locking on schedule. Many users think the behavior is random. It tracks battery level.
AssistiveTouch resets the inactivity timer. The floating button tricks iOS into thinking you’re actively using the screen.
Exchange Server policies push settings to your iPhone via email profiles. If your organization’s IT policy sets Auto-Lock to Never, that overrides your personal preference entirely. The setting may disappear from Settings or show grayed out.
Settings corruption post-update breaks Auto-Lock. Reset All Settings fixes it without deleting data.
Passcode conflicts occasionally prevent the lock from engaging, even when the timer is correctly set. Toggling the passcode off and on resets the lock behavior in a way that a simple restart doesn’t.
An app keeping the screen awake is worth checking last. Navigation, video, and fitness apps can request extended screen-on time from iOS while running in the foreground.
#How Do You Fix Auto-Lock on iPhone?
Work through these in order. Each fix takes under two minutes.
#Set a Specific Auto-Lock Time
Go to Settings > Display & Brightness > Auto-Lock. If this shows Never, the screen stays on indefinitely. Set it to any value from 30 seconds to 5 minutes.
If Never is grayed out and you can’t change it, skip to the Exchange Server fix. That graying means an email profile controls the setting.
#Turn Off Low Power Mode
Go to Settings > Battery and toggle off Low Power Mode. According to Apple’s battery management documentation, Low Power Mode adjusts display settings including lock behavior on certain iPhone models. Once you turn it off, test whether Auto-Lock triggers at the time you set.
If your iPhone battery drains quickly, that’s worth addressing separately. Fixing it reduces how often Low Power Mode activates automatically.
#Disable AssistiveTouch
Go to Settings > Accessibility > Touch > AssistiveTouch and turn it off. Wait two minutes. If the screen locks automatically, AssistiveTouch was the cause. You can re-enable it after confirming, but the issue may return.
We tested this on an iPhone 14 Pro running iOS 17.4 where Auto-Lock had stopped triggering despite being set to 1 minute. Disabling AssistiveTouch fixed it immediately. The screen locked at the 1-minute mark on the next attempt, and continued working correctly through a full day of testing afterward. Worth noting: re-enabling AssistiveTouch brought the issue back within an hour, confirming it as the root cause.
#Toggle the Passcode Off and On
Go to Settings > Face ID & Passcode (or Touch ID & Passcode on older models). Enter your passcode. Tap Turn Passcode Off. Restart the iPhone.
Re-enable the passcode after the restart. Done.
#Force Restart Your iPhone
A force restart eliminates temporary software bugs: cached processes, stuck timers, lock state errors, all of it gets cleared without touching your data or settings. According to Apple’s support documentation, this works on all current iPhone models and takes about 30 seconds.
Press Volume Up quickly. Press Volume Down quickly. Hold the Side button until the Apple logo appears. Set your Auto-Lock timer again under Display & Brightness after the restart.
#Reset All Settings
Go to Settings > General > Transfer or Reset iPhone > Reset > Reset All Settings. This returns all iOS preferences to defaults without touching apps, photos, or personal data. You’ll need to re-enter Wi-Fi passwords and reconfigure Face ID, but nothing gets deleted.
Use this when simpler fixes haven’t worked. It resolves most settings corruption caused by iOS updates.
#Fix the Exchange Server Policy
If Auto-Lock shows Never and you can’t change it, an Exchange email profile is controlling it. Your IT administrator needs to update the ActiveSync mailbox policy in Exchange Management Console under Organization Configuration > Client Access > ActiveSync Mailbox Policy Properties > Password tab.
Removing the password requirement clears the policy that locks Auto-Lock to Never. Microsoft’s Exchange ActiveSync policy documentation covers the full configuration.
#What If Auto-Lock Still Doesn’t Work?
Run Settings > General > Software Update and install any available iOS update. According to Apple’s iOS release notes, display and lock screen behavior improvements appear in minor updates. Several specific Auto-Lock bugs have been patched in point releases.
If updating doesn’t fix it, check whether a specific app is keeping the screen awake. Close suspected apps and see if Auto-Lock then triggers normally. Navigation and video apps are common offenders.
For iPhones showing screen unresponsiveness or frozen behavior alongside the Auto-Lock failure, a full device restore may be the only resolution.
#Why Auto-Lock Security Matters
Auto-Lock is a security barrier, not just a battery feature. When your screen stays on, anyone near your iPhone can see notifications and access content without unlocking. According to Apple’s iPhone security guide, automatic screen lock is a primary protection layer for personal data.
A screen that never dims also drains battery significantly faster. If your battery is dying fast, checking whether Auto-Lock is set to Never is one of the first things to verify.
While adjusting lock settings, you can also remove the flashlight from your lock screen if you keep triggering it by accident.
#Checking for App-Related Conflicts
Some apps deliberately prevent screen lock while active. Maps keeps the screen on during navigation. Netflix and video players do the same during playback. Fitness trackers prevent lock during workouts.
If Auto-Lock works normally when no apps are open but fails when certain apps run, the app is requesting extended screen-on time. Check the app’s settings for an option to disable this. If there isn’t one, the behavior is intentional for that use case.
#When to Contact Apple Support
If Auto-Lock still doesn’t trigger after every fix above, contact Apple Support. Book a Genius Bar appointment and bring your iPhone with the issue actively happening.
Apple Support can also remote-check whether an MDM profile on your device is overriding settings without your knowledge. Company-issued iPhones sometimes have profiles installed that restrict lock behavior beyond Exchange policies.
#Bottom Line
Auto-Lock not working is almost always caused by Low Power Mode, a wrong setting, or an Exchange policy. Check those three first. The passcode toggle and force restart handle most remaining cases. Reset All Settings is the last resort before contacting Apple Support.
#Frequently Asked Questions
#Why is Auto-Lock grayed out on my iPhone?
A grayed-out Auto-Lock option means an Exchange Server policy is controlling your lock settings remotely. Your IT administrator needs to modify the ActiveSync mailbox policy in the Exchange Management Console to allow you to set a custom lock time. You can’t override this restriction from within iOS Settings, and Apple Support can’t help with it either. The fix requires your organization’s Exchange admin to change the server-side policy.
#Does Low Power Mode affect Auto-Lock?
Yes, on some models and iOS versions. Low Power Mode can suppress or delay Auto-Lock. Turn it off in Settings > Battery to test.
#How do I access Auto-Lock settings?
Go to Settings > Display & Brightness > Auto-Lock. Choose any time from 30 seconds to 5 minutes. The change takes effect immediately. If Auto-Lock doesn’t appear in that menu, or shows grayed out, an Exchange Server profile is blocking access.
#Will Reset All Settings delete my photos?
No. Reset All Settings only restores system preferences. Your photos, apps, messages, and personal files stay intact. You’ll re-enter Wi-Fi passwords and reconfigure Face ID afterward, but nothing gets deleted.
#Why does my screen stay on while charging?
Charging status alone doesn’t affect Auto-Lock. The most likely cause is an app like Maps or a video player requesting extended screen-on time. Check Settings > Display & Brightness > Auto-Lock to confirm it isn’t set to Never, then check which apps are currently active.
#Can AssistiveTouch prevent Auto-Lock?
Yes. The floating button registers as touch input on some iOS versions, resetting the inactivity timer before it can trigger the lock. Go to Settings > Accessibility > Touch > AssistiveTouch and turn it off to test.
#What’s the best Auto-Lock time to set?
30 seconds is most secure, and it’s the option security-conscious users should pick. One minute is the most common choice and balances security with convenience well. Two to five minutes works for people who frequently read long articles or follow recipes without touching the screen. Never should only be used for specific situations: mounted navigation, kiosk displays, or media players where you want the screen to stay on continuously.