Software⏱️ 3 min read📅 2026-06-19

How to Fix: HyperV Error: "The computed authentication tag did not match the input authentication tag."

HyperV Error: The computed authentication tag did not match the input authentication tag.

Quick Answer: Check the virtual machine's TPM settings and ensure they match the system TPM settings.

📋 Table of Contents

  1. 🔍 Why This Happens
  2. 🔧 Proven Troubleshooting Steps
  3. 💡 Conclusion

The 'HyperV Error: The computed authentication tag did not match the input authentication tag.' error occurs when Hyper-V is unable to authenticate with the Trusted Platform Module (TPM) device, which is required for virtual machine restore. This issue affects users who rely on TPM-based virtual machines and are experiencing difficulties starting their virtual machines.

This error can be frustrating as it prevents users from accessing their virtual machines, causing downtime and impacting productivity. In this guide, we will walk you through the root causes of this error and provide two methods to resolve the issue.

🔍 Why This Happens

  • The primary reason for this error is that the TPM device's authentication tag does not match the computed authentication tag during virtual machine restore. This can occur due to several reasons, including a mismatched or incorrect TPM configuration, outdated drivers, or corrupted system files.
  • Another possible cause of this error is that the virtual machine's TPM settings are not properly configured or are set to use an incompatible authentication method.

🔧 Proven Troubleshooting Steps

Update TPM Drivers and Configuration

  1. Step 1: Step 1: Open the Device Manager and expand the 'TPM' section. Right-click on each TPM device and select 'Update driver'. Ensure that the latest drivers are installed.
  2. Step 2: Step 2: Check the virtual machine's configuration to ensure that the TPM settings are set correctly. In the Hyper-V manager, navigate to the virtual machine's properties and verify that the TPM settings are enabled and configured correctly.
  3. Step 3: Step 3: If using a third-party TPM driver, uninstall and reinstall it. This may resolve any compatibility issues.

Reset TPM Configuration and Virtual Machine

  1. Step 1: Step 1: Open the Command Prompt as an administrator and run the command 'bcdedit /set hypervisorlaunchtype auto'. This will reset the Hyper-V launch type to automatic.
  2. Step 2: Step 2: Restart your computer to apply the changes. During startup, select the virtual machine from the boot options. If prompted, enter the TPM authentication code to complete the restore process.

💡 Conclusion

To resolve the 'HyperV Error: The computed authentication tag did not match the input authentication tag.' error, try updating your TPM drivers and configuration or resetting the TPM configuration and virtual machine. If issues persist, consider seeking further assistance from Microsoft support or a qualified IT professional.

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