How to Fix “A Critical System Process C:\WINDOWS\system32\lsass.exe Failed” Error in Windows 11

Is your Windows PC plagued by the dreaded “Critical System Process Failed” error, often accompanied by a Blue Screen of Death (BSOD)? This frustrating issue, frequently linked to the lsass.exe process, can trigger unexpected reboots and disrupt your workflow. But don’t despair! This comprehensive guide offers proven solutions to diagnose and resolve this critical system error, getting your computer back on track.

The lsass.exe (Local Security Authority Subsystem Service) is a vital component of Windows, responsible for security-related functions like user authentication and security policy enforcement. When this process malfunctions, it can lead to the “Critical System Process Failed” error. Let’s dive into the most effective troubleshooting steps.

1. Eliminate Problematic Updates

A recently installed Windows update is often the culprit. Here’s how to roll back the update and prevent its reinstallation:

Access Update History: Open the Settings app (Win + I), go to Windows Update, and then click Update history.

Uninstall the Update: Select Uninstall updates and identify the most recent update. Click Uninstall.

Block the Update: Download and run the Microsoft “Show or Hide Updates” tool. This tool lets you hide the problematic update, preventing it from being installed again.

2. Disable Fast Startup

The Fast Startup feature can sometimes interfere with system processes. Try disabling it:

Open Control Panel: Search for “Control Panel” in the Start menu.

Power Options: Select Power Options.

Change Settings: Click Choose what the power buttons do, then Change settings that are currently unavailable.

Disable Fast Startup: Uncheck Turn on fast startup (recommended) under Shutdown settings. Save your changes.

3. Run SFC and DISM Scans in Safe Mode

Safe Mode loads only essential drivers and services, helping pinpoint the source of the problem.

Enter Safe Mode: Restart your PC while holding the Shift key. Navigate to Troubleshoot > Advanced options > Startup Settings > Restart. Press F4 to boot into Safe Mode.

Open Command Prompt as Administrator: Search for “cmd” in the Start menu, right-click Command Prompt, and select Run as administrator.

Run SFC Scan: Type sfc /scannow and press Enter. This checks and repairs corrupted system files.

Run DISM Scan: After the SFC scan completes, type DISM /Online /Cleanup-Image /RestoreHealth and press Enter. This repairs the Windows image.

Check Disk: Optionally, run chkdsk C: /f /r /x. This command checks the disk for errors. Allow the scan to complete and then reboot your PC.

4. Conduct a Malware Scan

Malware can interfere with system processes. Perform a comprehensive scan:

Open Windows Security: Search for “Windows Security” in the Start menu.

Virus & Threat Protection: Click Virus & threat protection, then Scan options.

Run a Full Scan: Select Full scan and click Scan now.

5. Update or Reinstall Drivers

Outdated or corrupted drivers can cause this error.

Open Device Manager: Right-click the Start button and select Device Manager.

Identify Problem Devices: Look for devices with a yellow triangle. Right-click the problematic device and select Update driver. Choose Search automatically for drivers.

Reinstall Drivers (If Necessary): If updating doesn’t work, right-click the device, select Uninstall device, and restart your PC. Windows will attempt to reinstall the driver.

6. Reset Windows (Last Resort)

If other methods fail, resetting Windows can resolve the issue. Back up your data before proceeding.

Open Settings: Go to System and select Recovery.

Reset This PC: Click the Reset PC button.

Choose Your Options: Select whether to keep your files or remove everything. Follow the on-screen prompts to complete the reset.

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