Blue screen (BSOD): how to read the stop code and fix it

A blue screen means Windows stopped itself to protect your data. The stop code on the screen is the clue to the cause.

What you seeYour PC ran into a problem and needs to restart. Stop code: ...

What it means

Windows shows the blue screen (black on some Windows 11 versions) when it meets an error it cannot recover from safely. It saves a small crash report, restarts, and usually carries on. One blue screen in months is not a worry. Repeated ones need attention.

First, note two things

1. The stop code at the bottom, in capital letters, such as CRITICAL_PROCESS_DIED, MEMORY_MANAGEMENT or DRIVER_IRQL_NOT_LESS_OR_EQUAL.
2. "What failed", if shown: a file name ending in .sys. That file belongs to a driver, and its name often tells you which device is at fault.

If the screen vanished too fast, open Settings › System › About after the restart to confirm Windows is running, then look in Reliability Monitor: press the Windows key, type reliability and open "View reliability history". Red crosses mark each crash, with the code.

What changed recently?

Most blue screens follow a change. Think back:

• a new device, RAM or disk fitted;
• a driver or Windows update installed;
• new software, especially antivirus, VPN or "tuning" tools;
• the computer overheating, or a knock or fall.

Undo the change first: unplug the new device, uninstall the new program (Settings › Apps › Installed apps), or remove the latest update (Settings › Windows Update › Update history › Uninstall updates).

Fixes, easiest first

1. Unplug everything extra: printers, USB hubs, drives, dongles. Restart and see whether the crashes stop.
2. Install pending updates: Settings › Windows Update › Check for updates, and then Advanced options › Optional updates for driver updates.
3. Update or roll back the driver named on the screen. Right-click Start › Device Manager, find the device, right-click › Properties › Driver. Use Roll Back Driver if the trouble began after an update, otherwise Update driver. Graphics drivers are best taken from the maker's own website.
4. Check system files with the two commands on our repair commands page.
5. Test the memory: press Windows key + R, type mdsched and choose "Restart now and check for problems".
6. Check the disk: see the same repair commands page for chkdsk.
7. Check temperature and dust. A laptop that is hot to the touch, with a roaring fan, needs its vents cleaned and a hard, flat surface under it.
8. Use System Restore to go back to a date before the trouble. See System Restore.

If Windows will not start at all

After two or three failed starts, Windows opens its recovery screen by itself. From there choose Troubleshoot › Advanced options for Startup Repair, System Restore, Uninstall Updates and Safe Mode. See Safe Mode and automatic repair loop.

When it is hardware

Crashes that continue in Safe Mode, appear with different stop codes each time, or happen during the memory test point to failing hardware: RAM, the disk, or overheating. Back up your files now (see back up first) and take the computer to a technician.

For Windows 11 and Windows 10. Written in November 2026. Menus move between updates; use the search box in Settings if a name differs. Back up important files before any step that resets, repairs a disk or opens the computer. This is an independent guide, not connected with Microsoft.