How to Fix "Verifying Shim SBAT Data Failed" Error on Computer?

Why Does This Terrible Security Error Keep Stopping Your Computer from Starting?

The "Verifying shim SBAT data failed: Security Policy Violation" error hits computers hard. This problem shows up when you have both Windows and Linux on the same machine. Your computer gets stuck. It won't start properly.

Here's what happens inside your computer. Windows sends out updates that make security rules tighter. These new rules don't like old Linux startup files. The Linux bootloader becomes outdated. Secure Boot sees this as dangerous. It blocks Linux from starting up.

Think of it like a security guard at a building. The guard gets new rules about who can enter. Your Linux system has an old ID card. The guard won't let it in anymore.

This error frustrates many users. But don't worry. Several proven methods can fix this problem completely.

What Causes This Security Problem?

The root cause lies in how different operating systems talk to each other. Microsoft updates Windows regularly. These updates change security settings. Linux systems don't always keep up with these changes fast enough.

Your computer has something called SBAT (Secure Boot Advanced Targeting). This feature checks if startup files are safe. When Linux uses old startup files, SBAT says "no way" and blocks everything.

The conflict happens because:

• Windows updates security rules frequently
• Linux bootloaders update more slowly
• Your computer tries to protect itself
• Old and new security rules clash

Solution 1: Update Your Linux Bootloader Safely

This method works best for most people. You'll turn off security temporarily. Then update the problem files. Finally, turn security back on.

Step 1: Turn Off Secure Boot

1. Restart your computer
2. Press the special key during startup (usually Del, F2, F10, or Esc)
3. Find the Boot or Security section
4. Change Secure Boot to "Disabled"
5. Save changes and exit

Step 2: Fix the Linux Files

1. Start your Linux system
2. Open the command window (Ctrl + Alt + T)
3. Type: sudo mokutil --set-sbat-policy delete
4. Restart once
5. Open command window again
6. Type: sudo apt update && sudo apt upgrade shim-signed
7. Restart again

Step 3: Turn Security Back On

1. Go back to BIOS settings
2. Change Secure Boot to "b"
3. Save and exit

Your computer should start normally now. The Linux files are updated and trusted.

Solution 2: Change Which System Starts First

Sometimes the problem isn't the files themselves. It's the order your computer tries to start things. Windows and Linux both want to be the boss. You can tell your computer which one to listen to first.

How to Change Boot Order:

1. Enter BIOS during startup
2. Go to the Boot section
3. Find "Boot Priority" or similar option
4. Move "Windows Boot Manager" to the top
5. Move Linux entries (GRUB, Shim) lower down
6. Save changes

This makes Windows start first. Linux becomes the backup option. The security error often goes away because Windows handles the startup process.

Solution 3: Turn Off Fast Boot Feature

Fast Boot sounds good. It makes computers start faster. But it can cause problems with multiple operating systems. This feature skips important checks. Sometimes those checks are needed for Linux to work properly.

Disabling Fast Boot:

1. Enter BIOS settings
2. Look for "Fast Boot" option
3. Set it to "Disabled"
4. Save changes and restart

Your computer will take a few extra seconds to start. But it will check everything properly. This often fixes the security error.

Solution 4: Reset Windows Completely

This method works when you don't need Linux anymore. It removes all Linux files from your computer. Windows becomes the only operating system. All security conflicts disappear.

Warning: This removes Linux completely. Make sure you don't need it first.

Reset Process:

1. Force restart your computer 3-4 times
2. Wait for "Automatic Repair" screen
3. Click "Troubleshoot"
4. Select "Reset this PC"
5. Choose "Keep my files" or "Remove everything"
6. Follow the steps shown

Windows will clean everything up. Your computer will start normally again.

Preventing This Error in the Future

Keep your systems updated. Linux distributions release security updates regularly. Install them when they become available. This prevents the security mismatch from happening again.

Also, check your BIOS settings occasionally. Some updates can change these settings automatically. Make sure everything still looks correct.

This security error looks scary but it's fixable. The methods above work for most computers. Start with the simplest solution first. If that doesn't work, try the next one.

Remember, this error happens because your computer tries to protect you. It's actually a good thing, even though it's annoying. Once you fix it properly, your computer will be both secure and functional.

Don't let this error stop you from using your computer. Pick the method that fits your needs. Follow the steps carefully. Your computer will start normally again.