The ERROR_SYSTEM_IMAGE_BAD_SIGNATURE (637) in Windows 11 signals that a critical system file or driver is not properly signed, prompting Windows to replace the file and shut down the system to protect against potential threats. This error can interrupt work, cause unexpected shutdowns, and may point to underlying corruption in system files or device drivers. Addressing the root cause as soon as possible helps restore system reliability and prevents recurring blue screen errors.

Run SFC and DISM Scans to Repair System Files

Step 1: Start your computer in Safe Mode with Networking. Press Windows + R, type msconfig, and press Enter.

Step 2: Go to the Boot tab, select Safe boot and Network, then click Apply and OK. Restart your PC to boot into Safe Mode.

Step 3: Open Command Prompt with administrator privileges. Press the Windows key, type cmd, right-click Command Prompt, and select Run as administrator.

Step 4: Scan and repair system files by entering the following command and pressing Enter:

sfc /scannow

This process checks for corrupted or missing system files and replaces them with healthy copies from the Windows cache.

Step 5: If the error persists after SFC, use the Deployment Image Servicing and Management (DISM) tool to repair the system image. Enter the following command and press Enter:

Dism /Online /Cleanup-Image /RestoreHealth

DISM connects to Windows Update to fetch and replace damaged system files. Let the scan finish, then restart your PC to apply changes.

Update or Reinstall Device Drivers

Step 1: While still in Safe Mode, press Windows + R, type devmgmt.msc, and press Enter to open Device Manager.

Step 2: Look for devices with a yellow triangle and exclamation mark, which indicates a problematic driver. Right-click the device and select Update driver.

Step 3: Choose Search automatically for drivers. If Windows cannot find an update, visit the manufacturer’s website to download and install the latest driver manually. Alternatively, use a trusted third-party driver updater tool to streamline this process.

Step 4: If updating does not resolve the issue, right-click the problematic driver and select Uninstall device.

Step 5: Confirm the action, then restart your PC or select Action > Scan for hardware changes in Device Manager to prompt Windows to reinstall the driver.

Run CHKDSK to Repair Disk Errors

Step 1: Open Command Prompt as administrator in Safe Mode as described earlier.

Step 2: Enter the following command, replacing C with the letter of your system drive, and press Enter:

chkdsk C: /f /r

This command scans the disk for bad sectors and file system errors, repairing any issues it finds. If prompted to schedule the scan at the next restart, type Y and press Enter, then restart your computer.

The scan may take a while, especially on large or error-prone disks. Review the summary upon completion or check Event Viewer for detailed results.

Disable Driver Signature Enforcement (Temporary Workaround)

Step 1: In Safe Mode, open Settings by pressing Windows + I. Go to System > Recovery.

Step 2: Under Advanced Startup, click Restart now. Wait for your PC to reboot to the Choose an option screen.

Step 3: Select Troubleshoot > Advanced options > Startup Settings, then click Restart.

Step 4: When presented with startup options, press F7 or 7 to disable driver signature enforcement. This allows the system to load unsigned drivers, which can temporarily bypass the error, but reduces system security. Only use this method if you trust all installed drivers and revert the setting as soon as possible.

Perform a System Restore

Step 1: In Safe Mode, press Windows + R, type rstrui, and press Enter to open the System Restore wizard.

Step 2: Select Choose a different restore point and click Next. Pick a restore point created before the ERROR_SYSTEM_IMAGE_BAD_SIGNATURE first appeared.

Step 3: Click Next, then Finish to begin system restoration. Your PC will restart and revert system files and settings to the selected state. If the restore fails, unresolved driver or file corruption may be the cause.

Reinstall Windows 11 as a Last Resort

Step 1: Back up all important files, documents, and application licenses to an external drive or cloud storage. Ensure you have your Microsoft account credentials and a list of installed software.

Step 2: On a working computer, visit the official Windows 11 download page and download the Media Creation Tool. Use it to create a bootable USB installation drive (at least 8GB capacity).

Step 3: Insert the USB drive into the affected PC, restart, and boot from the USB. If necessary, adjust the boot order in your device’s BIOS or UEFI settings.

Step 4: Follow the on-screen prompts to install Windows 11. Choose your language, edition, and partition as needed. Completing a clean installation removes all problematic files and drivers, restoring system stability. After installation, check for Windows Updates and reinstall necessary drivers and applications.

Resolving ERROR_SYSTEM_IMAGE_BAD_SIGNATURE (637) in Windows 11 involves repairing system files, updating or reinstalling drivers, addressing disk errors, and restoring or reinstalling the OS if needed. Taking these steps restores system reliability, prevents shutdowns, and helps you avoid recurring blue screen errors.