Reviewed: September 21, 2026. An Android phone that restarts by itself can have very different causes. A restart at roughly the same time while the phone is idle is not the same problem as a reboot during gaming, charging, opening one app, or a device that never reaches the Home screen.
The fastest route to a useful diagnosis is to identify the restart pattern first. This guide separates normal or scheduled restarts from app instability, overheating, power-button problems, battery or charging faults, and a true boot loop. Menu names vary across Samsung Galaxy, Google Pixel, Motorola, OnePlus, Xiaomi and other Android devices, so use the equivalent settings on your model.
First, identify what “keeps restarting” means
Before changing settings, note when the restart happens. If it occurs only at night or when the phone is idle, check automatic optimisation or scheduled restart features. If it happens after installing an app, test that app path. If it happens under heavy load or while charging, temperature and power become more important clues. If the phone repeatedly shows the manufacturer logo and never finishes starting, treat it as a boot-loop problem rather than an ordinary random reboot.
Also distinguish a restart from the screen simply going black. If the manufacturer boot logo appears again, Android really restarted. If the display turns off but calls, vibration or audio continue, the display or proximity behavior may be the actual issue.
1. Check for scheduled or automatic restarts
Some Android manufacturers include maintenance features that can restart the phone automatically. Samsung, for example, documents Restart when needed and Restart on schedule under Device care and Auto optimisation. A phone that restarts at predictable times while it is not being used may therefore be working as configured rather than crashing.
On a Galaxy device, check Settings > Device care > Auto optimisation > Auto restart. Other brands may place similar controls under Battery, System, Device care or scheduled power settings. Do not disable a feature permanently just because it exists; first compare its schedule with the time of the unexplained restart.
Samsung also notes that critical security updates can require a reboot. A one-off restart immediately after an update is therefore different from repeated random restarts.
2. Look at what changed just before the problem started
If the reboots began after installing or updating an app, that timing is useful evidence. Update the app and Android first. If the problem continues, uninstall the most recently added or suspicious app and test again rather than removing many apps at once.
A controlled one-change-at-a-time test preserves the evidence. If one specific app also freezes, closes unexpectedly or refuses to open, follow our Android app crashing troubleshooting workflow before clearing its data or resetting the entire phone.
3. Use Safe Mode to separate downloaded apps from the system
Safe Mode starts Android with downloaded third-party apps disabled. Samsung’s current troubleshooting guidance specifically recommends it for repeated reboots: if the phone becomes stable in Safe Mode, a downloaded app is the likely cause.
The exact Safe Mode procedure differs by manufacturer. On many Galaxy devices, open the power menu, touch and hold Power off, then choose Safe mode. Once booted, use the phone long enough to cover the period or action that normally triggers the restart.
If the restart disappears in Safe Mode, remove recently installed apps one by one, returning to normal mode to test after each change. If the restart continues in Safe Mode, the evidence shifts away from ordinary third-party apps and toward system, power, temperature or hardware causes.
4. Check whether heat triggers the restart
Heavy gaming, camera recording, navigation, hotspot use and charging can all raise device temperature. Android devices can reduce performance or shut down to protect hardware when thermal limits are reached. If reboots happen only when the phone is hot, stop the workload, disconnect charging and let the device cool naturally in a shaded, ventilated place.
Do not use ice, a freezer or rapid cooling. If the phone repeatedly becomes abnormally hot during light use or while idle, use our Android overheating diagnostic guide to isolate charging, apps, network activity and battery warning signs.
5. Inspect the power or side button
A case that presses the side key, debris around the button, impact damage or a physically sticking key can create behavior that looks like software instability. Remove the case temporarily and check whether the button moves and clicks normally. Do not insert sharp tools or liquids around the key.
If the side key feels stuck, behaves inconsistently or also fails when you intentionally try to lock or wake the phone, see our Android power button troubleshooting guide. A physical key problem should be resolved before a factory reset, because erasing software cannot repair a jammed switch.
6. Test the charging and power path
If restarts happen mainly while charging, unplug the charger and compare behavior on battery power. Then test with a known-good, standards-compliant cable and adapter appropriate for the phone. Inspect the USB-C port for obvious moisture, damage or debris without putting metal objects inside it.
If the phone restarts when the cable moves, repeatedly stops charging, or becomes unusually hot at the connector, investigate charging separately with our Android charging troubleshooting guide.
Restarts that correlate with a low battery percentage, sudden percentage drops, swelling, a lifting back panel or unexplained shutdowns can also point to battery or power-delivery problems. Stop using or charging a device with a visibly swollen or damaged battery and seek qualified service.
7. Install pending system and app updates
If the phone is stable enough to use, check for Android system updates and Play Store app updates. Manufacturers may fix stability problems through firmware, system components or app updates. After installing an update, allow the phone to complete its normal post-update restart and background optimisation before judging whether the problem remains.
Do not repeatedly force restarts while an update is actively installing. If the device cannot complete startup after an update, move to the boot-loop section below.
8. If it is stuck in a boot loop, change the priority
A boot loop means the phone repeatedly reaches a startup logo or animation but cannot finish booting. First disconnect nonessential USB accessories and remove the case if it may be pressing a button. Charge the device with a known-good charger for a reasonable period, then try the manufacturer’s documented forced-restart procedure.
If Safe Mode is reachable, use it to test whether a downloaded app is responsible. If the phone cannot reach Safe Mode or the Home screen, do not improvise with random recovery-menu commands from another model: key combinations and recovery options vary, and selecting a data-wipe option can erase the device.
Use the support instructions for your exact manufacturer and model. If important data is not backed up, avoid a factory reset until you understand the data-loss consequence.
9. Treat repeated restarts after a drop, water exposure or repair as hardware evidence
If the problem began immediately after a hard impact, liquid exposure, battery replacement or other hardware repair, software troubleshooting has lower diagnostic value. Intermittent power delivery, damaged connectors, battery faults or board-level problems can all present as restarts.
Back up important data while the phone remains stable enough to do so. Persistent restarts in Safe Mode, especially when combined with physical damage, abnormal heat or charging instability, justify manufacturer or qualified repair diagnostics.
10. Factory reset should be near the end, not the beginning
A factory reset erases user data and settings. It can help when persistent software corruption is the cause, but it cannot repair a sticking button, failing battery, damaged USB-C port or thermal hardware problem. Before resetting, back up important data and confirm that you know the Google or manufacturer account credentials required after the reset.
If you do reset, test the phone before restoring every app. A clean-device test is much more informative: if the restart occurs before third-party apps and data are restored, the evidence points away from those apps.
A quick diagnostic map
Same time while idle: check scheduled or automatic restart settings. After one app: update it, test Safe Mode, then uninstall it if necessary. During charging: isolate cable, adapter, USB-C port and battery behavior. When hot: stop the workload and investigate thermal causes. When pressing or touching the side key: inspect the case and button. Manufacturer logo repeating endlessly: treat it as a boot loop and use model-specific recovery guidance.
Bottom line
Random Android restarts are easier to solve when you preserve the pattern instead of immediately erasing the phone. Check scheduled restarts, isolate recent apps with Safe Mode, separate heat and charging triggers, inspect the side key, and reserve a factory reset for persistent software cases after backup. If the phone still reboots in Safe Mode or shows battery, charging, heat or physical-damage warning signs, hardware service becomes the safer next step.
Sources: Samsung Support: What to do if your Samsung Galaxy device keeps restarting (updated September 2026); Samsung Support: Phone or tablet reboots repeatedly.
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