Troubleshooting
Samsung Galaxy keeps restarting? 7 things to check
7 fixes, 6 with a real screenshot from our Galaxy S26 (One UI 9.0) and Galaxy A57 5G (One UI 8.5). Try them in order.
Illustration
Quick answer
Often the phone restarts on purpose. Check Settings, Device care, Auto optimization, Auto restart, and Settings, Security and privacy, More security settings, Inactivity restart. If neither is on, remove recently installed apps one at a time, update the software and run Samsung Members diagnostics.
Well, a phone that reboots itself halfway through a message makes you wonder who is really in charge. Often the reason is a setting, not a fault. Samsung lists three features that restart a Galaxy by design: Auto optimization, Auto restart and, from One UI 8, Inactivity restart. Rule those out before looking for a fault. A restart right after a security update is also normal.
Step-by-step guide
Follow these steps in order. After each step, check if it works.
- 1
Open Auto optimization
Open Settings, Device care and scroll down to Auto optimization, under Performance.
- 2
Check Auto restart
It restarts the phone when it is idle, on a schedule or when memory runs low. Ours read Restart when needed: Off. Samsung recommends leaving it on if you never restart the phone yourself, so expect night-time restarts while it is on.
- 3
Check Inactivity restart
Settings, Security and privacy, More security settings. When on, a phone that stays locked for 72 hours restarts itself for security. It was on on our Galaxy S26.
- 4
Remove recently installed apps
Samsung says third-party apps can trigger unexpected restarts. Open Settings, Apps, the app, and tap Uninstall at the bottom of its App info page (Samsung Notes in our picture). Uninstall the apps you added just before the restarts began, one at a time, and test after each one.
- 5
Install the latest software
Settings, Software update, Check for updates. Our phone was on One UI 9.0.
- 6
Run a diagnostic test
Open Settings, Device care and tap Diagnostics under Additional care, between Software update and Maintenance mode: it tests the touch screen, sensors, charging and more. On our Galaxy S26 it first asked to update the Samsung Members app, which runs the tests; we tapped Cancel. The Samsung Members app has the same tests under Support, Phone diagnostics.
- 7
Still restarting? Back up and get it checked
Back up your data. If the restarts continue with no new apps installed, a battery or hardware fault is likely, and a Samsung service centre can test it.
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If you do not see this option
- There is no Inactivity restart switch Samsung says Inactivity restart arrived with One UI 8.0, so phones on older software do not have it. Source: Samsung Galaxy device appears to keep restarting
- Auto restart shows two switches Samsung names them Restart when needed (when memory use rises or the phone has not restarted for a while) and Restart on schedule. Turn off both to stop these restarts. Source: Samsung Galaxy device appears to keep restarting
If this does not work
- It still restarts with Auto restart off Samsung says a restart can still happen depending on the phone's condition. If it keeps happening, uninstall recent third-party apps, because a newly added app can be the troublemaker: Settings, Apps, the app, Uninstall.
- It restarted overnight after an update That is the phone looking after itself while you sleep. Samsung says that in some countries or regions, urgent security updates can restart the phone even when automatic downloads are switched off.
- Not sure which app is to blame? Start the phone in Safe mode, which runs without the apps you downloaded. If the restarts stop there, one of those apps is the cause: start a Samsung Galaxy in Safe mode.
Good to know
A worn battery can switch the phone off under load, which always seems to happen halfway through an important call: how to check battery health on a Samsung Galaxy phone.
Before handing the phone in: how to use Maintenance mode on a Samsung Galaxy before a repair.
Watch these steps
Watch on YouTubeThe same steps, recorded on our Galaxy S26 · opens YouTubeAbout this guide
- Device
- Android
- Shown on
- Samsung Galaxy S26 (SM-S942N, Korean model), One UI 9.0, Android 17 (build CP2A.260605.016.S942NKSU5BZJB), Samsung Galaxy A57 5G (SM-A576B), One UI 8.5, Android 16
- App
- Settings
- Real screenshots
- 6 of 7 steps
- What we did
- Observed: looked at each screen, changed nothing
- Checked
- November 2026
- Sources
- 2 official, linked below
The screenshots are from a Samsung Galaxy S26 with One UI 9.0 and Android 17, in Dark mode, apart from step 4, from our Galaxy A57 with One UI 8.5. Other Galaxy phones on One UI 8.5 and 9 use similar menus; on older One UI versions a few names and positions differ. We only looked at these screens on our phones and changed nothing.
Sources
Links checked November 2026. Menus and features can change with updates.Related guides
How to turn off or restart a Samsung Galaxy (One UI 9)How to play one app's sound on a different device on a Samsung GalaxyHow to update apps on a Samsung GalaxyHow to update a Google Pixel and its apps (Android 17)How to reset network settings on a OnePlus (OxygenOS 16)How to change the language of one app on a Google Pixel (Android 17)Did this guide work for you?
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