Win 10 / 11 · Maintenance

Windows PC restarts or shuts down on its own: find the cause

A PC that restarts without warning is logging why every single time. Reliability Monitor names the cause in a minute, and heat or the power supply are the two usual answers.

DifficultyMedium
Time20 min
RiskLow
ReversibleYes
PlatformWin 10 / 11
UpdatedAug 24, 2026

Written and tested by emdottech

What that means

Low risk. This fix only checks things, or changes settings you can switch back in the same place. This change is reversible — you can return to the previous state without professional help or data loss.

The Windows Reliability Monitor with a red X entry to read, 'not properly shut down' flagged as power-related, and a named driver flagged as the crash cause

What usually goes wrong

A restart with no Reliability Monitor entry at all means the machine lost power instantly, which points at hardware rather than Windows.
Investigate the first restart rather than waiting for a pattern, because the log detail is most useful while the event is recent.

Steps

01
- Open Reliability Monitor by searching 'reliability' in Start. Find the red X at the time it happened: 'Windows was not properly shut down' means power loss, a named driver means a crash.
02
- Stop it restarting before you can read the error: System Properties, Advanced, Startup and Recovery, untick 'Automatically restart'. A blue screen will now stay put with its stop code.
03
- Check temperatures under load with any monitoring tool. A CPU hitting its thermal limit shuts the machine down to protect itself, and that is the usual cause of restarts while gaming or rendering.
04
- Suspect the power supply if restarts happen only under heavy load with no blue screen and no log entry — that pattern means the PSU cannot deliver enough current.
05
- Test the memory: search for Windows Memory Diagnostic, run it and let it finish. Faulty RAM causes random restarts with no consistent trigger.

How to verify the fix

The PC runs a full working session, including whatever load triggered it before, without restarting once.

If this didn't fix it

If it restarts under load and temperatures are fine, size your PSU against your components before replacing anything else. If Memory Diagnostic reports errors, test one stick at a time to find which.

Next stop: the related fixes below, or start a guided diagnosis.

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Windows PC restarts or shuts down on its own: find the cause

What usually goes wrong

Steps

✓How to verify the fix

!If this didn't fix it

Related fixes

How to verify the fix

If this didn't fix it