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Last updated: Oct 21, 2023

Solved: The Specified Disk Is Not Convertible on Windows

Getting this error, “Virtual Disk Service Error: The specified disk is not convertible.”? This is fixable following a couple of tips and procedures shared in this article. You’re getting the error because you’re trying to convert an MBR drive to GPT or vice versa.

Please note, that converting disk tables is an advanced action, you should make backups of your files in the partition or drive before going on to do the conversion. Back to the error message, the common relatable causes include: you’re converting a system drive or low storage space on the drive.

Why "The Specified Disk Is Not Convertible" Error Happen?

As hinted above, this error could be showing up due to low storage space on the drive you’re trying to convert. But then, there are other possible causes such as disk compatibility, architecture, and software limitations. Interestingly, this article addresses the “Virtual Disk Service Error: The specified disk is not convertible.” error and how you can fix it.

1: The Specified Disk is Not Convertible Because the Size is Less than the Minimum Size Required

Insufficient free space on your drive could halt and disrupt a lot of disk management processes, which includes changing the partition table. If you’re converting to GPT, you will need to have a reasonable free space on the drive before the conversion process will work out successfully.

Possible Causes

When it comes to system faults, there are a thousand things that could point to the error. However, there are always the most common ones to be aware of. In this case, the possible reasons why you’re getting the “disk not convertible…” error include the following:

  • Misconfigured Disk Settings: Maybe there are custom setting made on the disk that restricts it from being converted into another file system format or partition table. If you can remember making any of such configurations, undo them.
  • Hardware Limitations: This includes the type of hard drive you’re using, the manufacturer and your storage system configurations.
  • Software Restrictions: Some buggy third-party software programs could be the reason why you’re getting the error; you may need to uninstall recently installed apps on your PC and try again. If the issue persists, use an alternative option (explained below).

Fix 1. Use An Easier Alternative to Disk Management

Since you’re getting the error while trying to use the Disk Management utility, maybe you should try an alternative method. Yes, there are disk/partition management software programs that allow you to carry out advanced actions like disk table conversions and others alike.

But since they are third-party applications, you should be careful which one you install and use. With a good third-party partition management software you can convert from MBR to GPT or vice versa without errors or data loss.

Fix 2. Clear the Read-Only Status via DiskPart

It could be that the disk you’re trying to convert is set to read-only, which means you cannot perform action on the drive until you change its read-only status. How do you get this done? Well, the Windows Disk Part utility can help to change the read-only status of drives. This is an admin-level action, so you must be logged in as an admin on the PC.

Steps:

CAUTION: Allow each command to run successfully before entering the next one. The “Clean” command will take longer and it’s going to erase any data on the selected disk/drive. So, before you run the DiskPart utility, make sure to back up all the files you have on the affected drive.

  • Right-click on the Start/Windows icon on the taskbar and select Command Prompt (Admin) / PowerShell (Admin)
  • When the CMD interface launches, type “Diskpart” and hit the enter button.
  • Now, enter these commands sequentially:
    • list disk
    • select disk X (Replace X with the actual disk number/letter of your read-only disk)
    • clean
    • convert GPT (or convert MBR if the drive is already in GPT)
    • exit
  • Close the CMD terminal when you’re done, then go and check if the drive has been removed from its read-only status.

Fix 3. Check If the Disk Status Is Online

What if the disk you’re trying to convert is not “Online?” Yes, the disk could be offline and you didn’t know. Disk status is shown in Disk Management – there, you will discover if all your connected drives are online and initialized. If a disk is not showing “Online” and “Initialized,” you cannot run any actions on that disk. Here’s how to perform this check and change your drive’s status.

Steps:

  • Right-click on the Start/Windows icon on the taskbar and select Disk Management
  • On the Disk Management interface, you will be able to see all drives (including external drives) connected to your PC.
  • If you find any of your disks showing “Offline,” right-click on that disk and set it to “Online”
  • Similarly, if any of your disks are not initialized, right-click and choose the initialization option.

Fix 4. Check Hard Disk Errors

If there are back sectors on the hard drive, you’ll be unable to successfully convert its partition table. One of the effective ways to check for errors and bad sectors on a hard drive is by using the Check Disk utility. The Check Disk utility is free and built into every Windows OS version; you run it through the command prompt and it’s an admin-level command. This utility will look for errors on your hard drive and attempt to fix them automatically.

Steps:

  • Right-click on the Start/Windows icon on the taskbar and select Command Prompt (Admin) / PowerShell (Admin)
  • When the CMD terminal launches, run this command: chkdsk /f /r
  • Wait for the scanning to run and complete successfully, then close the CMD terminal and check if the issue you’re facing is fixed.

2. The Specified Disk Is Not Convertible - CDROMs and DVDs Are Examples of Disks That Are Not Convertible

Not all “drives” and “disks” can be converted. If you’re trying to convert a DVD or CD drive, that won’t be possible. But then, if you’re trying to convert a dynamic disk, you need to first convert it into a basic disk, then proceed with changing the partition table to MBR or GPT. However, these are all high-level actions, you should back up your files before doing that.

Fix 1. Delete All Partitions on the Hard Disk and Initialize It to GPT

If the disk you’re trying to convert is not a CD-ROM or DVD, then you should try deleting all existing partitions, after which you should right-click on the drive and select “Initialize to GPT.” All these can be done on the Disk Management interface.

Fix 2. Convert MBR to GPT Without Data Loss Using DiskInternals Partition Recovery

DiskInternals Partition Recovery software is a program that helps you back up all your partition data before you can proceed to convert MBR to GPT. The software itself doesn’t convert MBR disks to GPT, it is only but a partition data backup and recovery solution that runs on all Windows OS versions.

Using this software program, you can be assured that all your files will be safe and after the conversion, you can restore back everything. It works in a simple way; you install it on your PC, select your disk, right-click and select “Create Image,” then choose where to save the disk image file.

These disk image files contain every info, file, and data on your drive – it’s a wholesome backup format.

Fix "The Specified Disk Is Not Convertible" Without Deleting Partitions

If you must use Disk Management or Diskpart to convert GPT to MBR or vice versa, you will need to delete all your partitions. But when you use third-party software solutions, you may not need to delete any partitions.

Alternatively, you could back up your partitions using DiskInternals Partition Recovery, then proceed with the GPT to MBR conversion, when it goes successfully, you can restore your partitions from the backup you created using DiskInternals software.

Tips to Protect Drive from "The Specified Disk Is Not Convertible" Error

You can actually try out some practical tips to keep your drive ready for GPT/MBR conversions. What does this mean? It means that these tips shared below can help you avoid getting the “Disk is not convertible…” error message when you want to change your drive’s partition table.

  • Don’t let your disk’s storage space get completely filled, always reserve a reasonable amount of storage space.
  •  Don’t intentionally set your drives to read-only, unless you don’t have future intentions of carrying out any configurations on the disk.

Conclusion

What more? The “Virtual Disk Service Error: The specified disk is not convertible” error message will only show up when scenarios as explained in this article come into play. To avoid facing this error message, this article also provides useful tips on what to do.

Most importantly, you should ensure to back up your files and data using a reliable software program like the DiskInternals Partition Recovery app before proceeding with any of the advanced solutions provided in this article. The need for making frequent backups can’t be over said.

FAQ

  • How do I get rid of virtual disk service error?

    • Leveraging Diskpart to Establish Volumes (Boot, System, RAID, and More)
    • Deploying DiskPart to Eradicate All Partitions on Windows.
    • Utilizing Diskpart to Transition from GPT Disk to MBR.
    • Applying Diskpart Techniques to Combine Partitions.
    • Top Alternatives to Diskpart for Windows 11/10/8/7.
  • Why can't i convert USB to MBR?

    The "Convert to MBR greyed out" issue arises because the selected disk has partitions on it. In Disk Management, only an unpartitioned disk can be converted to MBR or GPT. Consequently, if the disk you've chosen has partitions, the "Convert to MBR Disk" option will not be available.

  • What is the minimum size for GPT disk?

    For GPT drives, there's a specific partition called the EFI System Partition, often abbreviated as ESP. Typically found on the main hard drive, the device starts up from this partition. This partition should be at least 100 MB in size and it's imperative to format it using the FAT32 file system.

  • Why is the specified disk not convertible because the size?

    If your hard drive is set to offline or read-only mode, you might encounter the error message “The specified disk is not convertible because the size is less than the minimum size required for GPT” when trying to initialize the disk to GPT.

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