Windows blue screen: what to do, step by step, and what to avoid

A blue screen appears when Windows detects an error so serious that it stops to avoid damage. If it happened once, it is usually a one-off; if it keeps happening, something needs attention. These steps go in order, from simplest to most involved. Stop as soon as the problem goes away. On recent versions of Windows 11 the screen can look black, but it is the same error.

First, write down the stop code

While the screen is still up, take a photo. Write down the Stop code line (for example, CRITICAL_PROCESS_DIED) and the file named as the cause, if there is one. It is the most useful clue for a technician, and for looking the error up on Microsoft’s support site. If the computer restarted before you could see it, it is logged in Event Viewer (Windows Logs, System, event 1001) as a hexadecimal number, for example 0x000000EF; that also works for looking the error up.

Steps, in order

1. Restart. Windows usually does it by itself. If it froze on the blue screen, hold the power button until the computer turns off, then turn it back on.
2. Unplug anything you connected recently. USB drives, external disks, printers, webcams. Restart without them and, if all is well, plug them back in one at a time.
3. Undo the last change. If the problem started after you installed something, remove it:
   • a program: in Settings, open Apps and uninstall it;
   • a driver: in Device Manager, open the device’s properties and, on the Driver tab, use Roll Back Driver if available;
   • an update: in Windows Update, open the update history and choose Uninstall updates. If removing it fixed the problem, pause updates for a few days in Settings, Windows Update, and tell a technician;
   • anything else: if you have a restore point, try System Restore.
4. Install pending updates. In Settings, open Windows Update and choose Check for updates. If you paused updates, skip this one.
5. Check disk space. In Settings, open System, then Storage. If the disk is nearly full, free up space by deleting what you no longer use.
6. Use the tools built into Windows. Search for Windows Memory Diagnostic and choose Restart now and check for problems; it can take a while, and you shouldn’t turn the computer off while it runs. For the disk, in File Explorer right-click drive C, choose Properties, open the Tools tab and, under Error checking, choose Check. If the drive makes odd noises, skip that check.
7. Try Safe Mode. If the blue screen shows up every time you turn the computer on, Windows usually opens a recovery menu after a few failed starts. Go to Troubleshoot, Advanced options, Startup Settings, Restart, then choose Enable Safe Mode. If it doesn’t crash there, the cause is often something installed recently, so try removing it from there. If Windows does start, you can reach the same menu from Settings, under Recovery, with Advanced startup.

What not to do

• Edit the Windows registry to “fix” it.
• Download “repair” or “cleaner” programs: some are misleading or come with malware.
• Open the computer to move the memory or cables. If it has to be done, let a technician do it.
• Format or reinstall Windows before backing up your files.

When to stop and get help

Call a technician if:

• The blue screen keeps coming back even after the steps above.
• The drive makes odd noises, like clicking or grinding. Turn the computer off and don’t keep powering it on, since every start can make the damage worse.
• Important information has no backup. Before you try anything else, the priority is getting those files out.
• The computer won’t start even in Safe Mode, or asks for a BitLocker recovery key you don’t have.

If you have done all this and the blue screen persists, at iTech Los Cabos we provide technical support for computers. Keep the stop code handy and tell us what changed before the failure; that makes the diagnosis faster. Learn about our IT support service.