How To Windows

How to Fix MBR2GPT “Failed to Update ReAgent.xml” on Windows Computer

By Raj Bepari 4 min read
Recommended: Download Windows Speedup Tool to quickly fix PC issues.

The MBR2GPT utility is a built-in Windows tool that converts a system disk from Master Boot Record (MBR) to GUID Partition Table (GPT) without deleting your data or reinstalling Windows. It’s commonly used when upgrading from Legacy BIOS to UEFI, especially before installing or upgrading to Windows 11. While the conversion process is usually straightforward, some users encounter the error “Failed to update ReAgent.xml”, causing the conversion to fail before completion.

This error typically occurs because the Windows Recovery Environment (WinRE) configuration is corrupted, the ReAgent.xml file is missing or inaccessible, the Recovery partition is disabled, or Windows cannot update the recovery configuration during the conversion process. In some cases, insufficient permissions, disk errors, corrupted system files, or antivirus software can also interfere with the MBR2GPT process.

Fortunately, you can usually resolve the issue by checking the Windows Recovery Environment configuration, temporarily disabling WinRE, repairing system files, and recreating the recovery configuration if necessary. In this guide, we’ll walk you through the most effective methods to fix the MBR2GPT “Failed to update ReAgent.xml” error on Windows 11.

How to Fix MBR2GPT “Failed to Update ReAgent.xml” on Windows

Before you begin, create a full backup of your important data. Although MBR2GPT is designed to convert the disk without data loss, modifying partition tables and boot configurations always carries some risk. Also, ensure your system meets Microsoft’s requirements for MBR2GPT, including having no more than three primary partitions and sufficient unallocated space for the EFI System Partition.

1. Check the Current WinRE Status

First, verify whether the Windows Recovery Environment is enabled and configured correctly.

  1. Open Command Prompt as Administrator.
  2. Run:
reagentc /info
  1. Check the Windows RE status.
  2. Verify that the recovery image location is valid.

If WinRE is disabled or the recovery path is missing, MBR2GPT may fail to update the ReAgent.xml file.

2. Disable and Re-enable Windows Recovery Environment

Recreating the WinRE configuration often resolves ReAgent.xml errors.

  1. Open Command Prompt as Administrator.
  2. Disable WinRE by running:
reagentc /disable
  1. Restart your computer.
  2. Open Command Prompt again.
  3. Re-enable WinRE:
reagentc /enable
  1. Verify the configuration:
reagentc /info

This rebuilds the recovery configuration and creates a fresh ReAgent.xml file if needed.

3. Verify the Recovery Partition

A missing or damaged recovery partition can prevent WinRE from updating.

  1. Press Windows + X.
  2. Select Disk Management.
  3. Locate the Recovery Partition.
  4. Ensure the partition exists and isn’t marked as unhealthy.
  5. If the partition is missing or corrupted, recreate it before running MBR2GPT.

The Recovery partition stores the files required by Windows Recovery Environment.

4. Validate the Disk Before Conversion

MBR2GPT includes a validation mode that identifies configuration problems.

  1. Open Command Prompt as Administrator.
  2. Run:
mbr2gpt /validate /allowFullOS
  1. Review any reported errors.
  2. Resolve the reported issues before running the conversion.

Validation helps identify disk layout problems before making any changes.

5. Repair Corrupted System Files

Damaged Windows files can prevent WinRE from updating its configuration.

  1. Open Command Prompt as Administrator.
  2. Run:
sfc /scannow
  1. After the scan finishes, run:
DISM /Online /Cleanup-Image /RestoreHealth
  1. Restart your computer.

These tools repair Windows components required by MBR2GPT and WinRE.

6. Check the ReAgent.xml File

The configuration file may be missing or corrupted.

  1. Navigate to the Windows Recovery folder.
  2. Verify that ReAgent.xml exists.
  3. If the file appears corrupted, disable and re-enable WinRE using reagentc.
  4. Avoid manually editing the file unless instructed by Microsoft documentation.

Windows automatically regenerates the file when WinRE is reconfigured.

7. Temporarily Disable Antivirus Software

Security software may block changes to recovery files.

  1. Temporarily disable your antivirus.
  2. Run the MBR2GPT conversion again.
  3. Re-enable your antivirus after the process completes.

Only perform this step if you trust your system and are using built-in Windows tools.

8. Check the Disk for File System Errors

Disk corruption can prevent recovery files from being updated.

  1. Open Command Prompt as Administrator.
  2. Run:
chkdsk C: /f
  1. Press Y if prompted.
  2. Restart your computer.
  3. Allow the disk check to complete.

Replace C: with your Windows drive letter if different.

9. Install the Latest Windows Updates

MBR2GPT and WinRE improvements are often included in Windows updates.

  1. Open Settings.
  2. Go to Windows Update.
  3. Click Check for updates.
  4. Install all available updates.
  5. Restart your computer.

Updating Windows ensures you have the latest fixes for deployment and recovery tools.

10. Run MBR2GPT from Windows Recovery Environment

Running the conversion outside the full Windows environment may avoid conflicts.

  1. Boot into the Windows Recovery Environment or Windows installation media.
  2. Open Command Prompt.
  3. Run:
mbr2gpt /validate
  1. If validation succeeds, run:
mbr2gpt /convert

Running MBR2GPT in WinRE reduces interference from active Windows services.

11. Verify the Boot Configuration

An incorrect Boot Configuration Data (BCD) store can interfere with recovery updates.

  1. Open Command Prompt as Administrator.
  2. Run:
bcdedit
  1. Verify that the Windows boot entries are valid.
  2. Repair the BCD if necessary before running MBR2GPT.

A healthy boot configuration helps ensure the conversion completes successfully.

12. Perform an In-Place Repair Upgrade

If the error persists despite repairing WinRE, your Windows installation may be damaged.

  1. Download the latest Windows 11 ISO from Microsoft.
  2. Mount the ISO file.
  3. Run setup.exe.
  4. Choose Keep personal files and apps.
  5. Complete the repair installation.
  6. Retry the MBR2GPT conversion.

An in-place repair reinstalls Windows system components while preserving your files and applications.

Conclusion

The MBR2GPT “Failed to update ReAgent.xml” error is usually caused by problems with the Windows Recovery Environment, a corrupted or missing ReAgent.xml file, disk errors, or damaged system files. In most cases, checking the WinRE configuration, disabling and re-enabling the Windows Recovery Environment, repairing Windows files, and validating the disk before conversion will resolve the issue.

If the problem persists, verify the Recovery partition, run MBR2GPT from the Windows Recovery Environment, inspect the boot configuration, or perform an in-place repair upgrade. Keeping Windows 11 updated and ensuring the recovery environment is properly configured will help ensure successful MBR-to-GPT conversions and a smooth transition from Legacy BIOS to UEFI.

Raj Bepari

I’m a digital content creator passionate about everything tech.