Fix 0x0000027D: System Image Bad Signature Error

Cause 1: Driver Signature Enforcement Is Blocking a Boot Driver

The most common trigger for the 0x0000027D error is a driver that hasn't been digitally signed properly. You'll see this most often after a Windows Update (usually a quality update, not a feature update) or after installing a new piece of hardware—especially storage controllers, network adapters, or anti-cheat software for games.

Windows 10 and 11 both enforce driver signature checking at boot. If a driver in the boot path has a bad signature—or no signature at all—the system throws this error and stops loading.

Fix 1: Temporarily Disable Driver Signature Enforcement

This is the quickest way to see if driver signing is the root cause. You do it from the Windows Recovery Environment (WinRE).

1. Boot your PC from a Windows installation USB or DVD. If you don't have one, you can force WinRE by interrupting the boot sequence three times (turn off the PC as Windows starts loading).
2. On the first screen, pick your language and keyboard layout, then click Next.
3. Click Repair your computer in the lower-left corner.
4. Go to Troubleshoot > Advanced options > Startup Settings.
5. Click Restart. After the restart, you'll see a list of startup options.
6. Press F7 or 7 on your keyboard to select Disable driver signature enforcement.

After doing this, Windows should boot normally. If it does, you've confirmed the problem is a bad driver. Now you need to find the culprit.

Driver Troubleshooter: Finding the Bad Driver

Once you're back into Windows, open Event Viewer (press Win+R, type eventvwr.msc, press Enter). Go to Windows Logs > System. Look for events with Source BugCheck or Kernel-PnP around the time of the failed boot. The error details will often name the driver file (like xxx.sys).

Another method: open a Command Prompt as Admin and run:

verifier /standard /all

Reboot and let Driver Verifier stress-test your drivers. It'll crash with a blue screen that names the offending driver. Write that name down, then boot back into Safe Mode (hold Shift while clicking Restart) and uninstall the driver or update it from the manufacturer's site—never from a generic download site.

Cause 2: Corrupted Boot Configuration Data (BCD)

The BCD store contains a list of boot entries and their integrity checks. If the BCD itself gets corrupted—which happens after a failed update or a power loss during boot—Windows can't validate the system image signature and throws 0x0000027D.

Fix 2: Rebuild the BCD Manually

1. Boot into WinRE using the same steps as above (USB or forced boot interrupt).
2. Go to Troubleshoot > Advanced options > Command Prompt.
3. Type bootrec /scanos and press Enter. This scans for Windows installations. You should see at least one listed.
4. Type bootrec /rebuildbcd and press Enter. When prompted, press Y to add the installation to the boot list.
5. Type bootrec /fixmbr and press Enter.
6. Type bootrec /fixboot and press Enter. If you get an access denied error, try bootsect /nt60 SYS /mbr instead.
7. Close the Command Prompt and restart the PC.

After the rebuild, check if the error is gone. If you still see it, the boot files themselves might be damaged. Run sfc /scannow and dism /online /cleanup-image /restorehealth from the same Command Prompt—but note that these commands need a working Windows installation to run. If you're booting from a recovery disk, they won't work. In that case, you'll need to do a repair install using the Keep personal files and apps option.

Cause 3: Corrupted System Files from a Failed Update

Sometimes the problem isn't a driver or the BCD—it's the system image file itself. A Windows Update can leave a file in a partially signed state if the update was interrupted (power loss, forced shutdown, disk full). This error code specifically mentions %s as the offending file, which is the system image. In practice, that's often ntoskrnl.exe or winload.exe.

Fix 3: Use System File Checker and DISM from a Bootable USB

1. Boot into WinRE and open Command Prompt as before.
2. Run sfc /scannow /offbootdir=C:\ /offwindir=C:\Windows. Replace C: with your actual system drive letter (it might be D: in WinRE). You can find out by running diskpart, then list volume.
3. If SFC reports corrupt files it can't fix, run DISM against the offline image:

DISM /Image:C:\ /Cleanup-Image /RestoreHealth /Source:ESD:\sources\install.esd:1 /LimitAccess

The /Source path points to the install.esd or install.wim file on your Windows installation media. You need to mount or insert the USB or DVD first, then figure out its drive letter (again, use diskpart). If you don't have installation media, you can skip the /Source switch—DISM will try to use Windows Update, but that won't work from WinRE. In that case, you're better off doing a repair install or a clean install.

Quick-Reference Summary Table

One final tip: if you're on a laptop that came with Windows pre-installed, check if the manufacturer has a BIOS update. Some bugs in UEFI firmware can cause signature verification failures even with valid drivers. Update the BIOS from the manufacturer's support page—don't use a third-party tool.