iPhone alarm not working after an iOS update? 7 fixes

You updated your iPhone, went to bed as normal, and the alarm never rang. It's one of the most common complaints after any iOS release — iOS 26.5 and 26.6 both produced a wave of them, and iOS 27 will too — and it almost always comes down to a setting the update reset or a Focus that came back switched on. Not a phone that's broken.

If you didn't just update and the alarm simply stopped working, the general list is iPhone alarm not going off? 8 causes and fixes. This page is for the morning after an update.

Updating to iOS 27? Read this first

iOS 27, rolling out from mid-September 2026, changes the alarm volume model — the biggest alarm change in years:

• Alarms get their own volume slider. In Settings → Sounds & Haptics there's a new Match Ringtone Volume toggle. Leave it on and alarms follow Ringtone and Alerts as before; turn it off and you get separate sliders for alarms, timers and alerts. Set the alarm one to maximum once and it stops being affected by anything you do to notification volume during the day. This is Apple's answer to the long-running silent-alarm complaints.
• Which means one new post-update check: after installing iOS 27, open Sounds & Haptics and look at what the update did with that toggle and the new sliders. A separate alarm slider that came through low is the new version of cause 3 below.
• The seven checks below still apply — a major update resets the same sounds, Focus states and Sleep-schedule handoffs that every update does, only more thoroughly.

Test an alarm the evening you install it, before you sleep on it.

Quick answer: an update doesn't delete your alarms, but it can reset the alarm sound, change the Ringtone and Alerts volume, re-enable a Focus, or leave a Sleep Schedule alarm in charge instead of your regular one. Work through the seven checks below, then test it before you trust it tonight.

1. Check the alarm is still there — and still on

Open Clock → Alarms and look at the toggle, not just the time. After a big update, or after restoring to a new iPhone, alarms can come back switched off, and a one-time alarm that already fired stays off by design. If you restored from a backup, alarms don't always come across at all.

2. The alarm sound got reset to None

This is the single most common cause of an alarm that "went off silently." Tap the alarm → Sound and check what's selected. If it says None, the alarm still fires — the banner appears, the phone may vibrate — but no audio plays. Pick a sharp, distinctive tone while you're there.

The full checklist for this failure mode is in iPhone alarm going off silently.

3. Ringtone and Alerts volume dropped

Alarm loudness is controlled by Settings → Sounds & Haptics → Ringtone and Alerts, and that slider is independent of the volume buttons you press while playing music. Updates sometimes leave it low. Drag it to maximum and listen — the phone plays a sample as you drag, so you'll hear exactly how loud tomorrow's alarm will be.

If it still sounds quiet, see iPhone alarm volume too low.

4. A Focus came back on

Focus settings are one of the things updates most often reshuffle. Apple's own Clock alarms ring through Do Not Disturb and every Focus, so a Focus alone can't silence them — but it's worth checking Control Centre anyway, because a Focus being active is a strong hint that Sleep Schedule is also running, which is cause number five.

The full picture on what Focus does and doesn't silence is in does Do Not Disturb silence alarms.

5. A Sleep Schedule alarm took over

If you use the Health app's Sleep Schedule, its wake-up alarm is a separate thing from the alarms in the Clock app, and it's deliberately gentler — softer default sounds, and it fires on your Apple Watch as haptics if you're wearing one. After an update it's easy to end up relying on that gentle alarm without realising your loud one isn't set.

Check Clock → Alarms: the Sleep Schedule alarm appears at the top under a "Sleep | Wake Up" heading, separate from your own alarms below. More on this in Sleep Focus alarm not going off.

6. A third-party alarm app needs attention

Third-party alarm apps take the hardest hit from updates. Many deliver their alarm as a notification, which means a Focus really can silence them, and permissions sometimes need re-granting after an update. Open the app, check its notification permission in Settings → Notifications, and make sure it's allowed through whatever Focus you sleep with.

Apps built on iOS's proper alarm support behave like the Clock app instead — WakeUpBroo uses AlarmKit, so it rings through Silent Mode, Do Not Disturb, and Focus the way Apple's own alarms do.

7. Restart the phone properly

If everything looks right and the alarm still misbehaves, power the iPhone fully off, wait ten seconds, and turn it back on. Updates occasionally leave background services in a bad state, and a genuine restart clears it. This is worth doing before you go hunting for anything more exotic.

Test it before you trust it

Don't find out at 7 a.m. Set an alarm for two minutes from now, lock the phone, put it down, and wait. You're checking three things: that it makes noise, that it's loud enough to hear from across the room, and that it keeps ringing rather than stopping after a few seconds.

Do this after every update. It takes two minutes and it's the only way to know.

If the alarm works fine and you still slept through it

Everything above fixes an alarm that didn't ring properly. If yours rang correctly and you slept through it — or turned it off with no memory of doing so — that's a different problem, and no settings change fixes it. See why you sleep through alarms.

The reason a working alarm still fails is that the off switch is within reach. WakeUpBroo has no snooze and no dismiss button: it stops only when you enter a rotating code from wakeupbroo.com/code on another device across the room. By the time you've walked over and typed it, you're genuinely up. Get it on the App Store, or compare approaches in the best alarm apps for heavy sleepers.

Bottom line

An iOS update doesn't break alarms, but it does reset the settings alarms depend on — sound, volume, Focus, and which alarm is actually in charge. Check those four first, restart if needed, and always run a two-minute test afterwards. The update isn't the problem; trusting it without testing is.