The Selected Disk Is Not a Fixed MBR Disk: Causes & Solutions

Getting the “The selected disk is not a fixed MBR disk” error in DiskPart? This error usually occurs when you run the active command on a GPT disk or in a UEFI boot environment.

In this guide, you’ll learn why this error occurs and how to fix it by repairing boot files, or converting GPT to MBR when necessary.

What Does “The Selected Disk Is Not a Fixed MBR Disk” Mean

The “The selected disk is not a fixed MBR disk” error usually appears when you run the active command on a GPT disk or in a UEFI boot environment.

For example, you may run these commands in DiskPart:

• diskpart
• list disk
• select disk 0
• list partition
• select partition 1
• active

You may then see this error:

• The selected disk is not a fixed MBR disk.
• The ACTIVE command can only be used on fixed MBR disks.

Therefore, if your system disk uses GPT and UEFI, running the active command can trigger this error. Before trying to fix it, check your disk’s partition style and boot mode to determine the appropriate solution.

Now, try these solutions to fix this issue.

UEFI vs BIOS – What’re the Differences and Which One Is Better

What are UEFI and BIOS? This article will tell you their differences via UEFI vs BIOS and show you how to convert MBR to GPT to support UEFI mode.

Read More

Method 1. Convert GPT Disk to MBR

As mentioned above, if your disk is GPT, the active command will always fail. And you will receive the error message “The selected disk is not a fixed MBR disk”.

Well, you need to convert the GPT disk to MBR. Here are two methods:

• Convert GPT to MBR without data loss – MiniTool Partition Wizard
• Convert GPT to MBR with data loss – DiskPart

Option 1. Convert GPT to MBR Without Data Loss

MiniTool Partition Wizard can help you convert GPT to MBR without data loss and then set the system partition as active. To perform successfully, you’d better use the MiniTool Partition Wizard bootable edition to convert.

MiniTool Partition Wizard DemoClick to Download100%Clean & Safe

Step 1. Make a bootable USB drive on a working computer.

1. Insert a USB flash drive into a working PC. Building bootable media will format your USB drive. So, you need to back up the USB drive data if there are important files.
2. Launch MiniTool Partition Wizard and click Bootable Media in the top right corner.
3. In the pop-up window, click WinPE-based media with MiniTool plug-in.
4. Select USB Flash Disk. You will be warned that the data on the USB disk will be destroyed. Click Yes, and then this tool will start to create a bootable drive.
5. Wait patiently until the process ends and click Finish.
6. Finally, eject the USB drive from the computer safely.

Step 2. Boot the problematic computer from the USB drive.

1. Plug the bootable USB drive into the problematic computer.
2. Restart the computer and then press the boot menu key (F2, F8, F9, F11, F12, Esc, etc.) immediately when the computer logo appears.
3. When the Boot Menu appears, select the bootable USB drive.
4. Then your computer will load from the USB drive and enter the main interface of MiniTool Partition Wizard after a while.

Step 3. Convert the GPT disk to MBR.

1. On the software’s main interface, select the system disk and click Convert GPT Disk to MBR Disk.
2. Click Apply in the bottom left corner.

Then you can continue with MiniTool Partition Wizard to set system partition active. And reboot your PC.

Option 2. Convert GPT to MBR With Data Loss

If you don’t want to download the third-party software, you can use DiskPart. But this can cause data loss. So, make sure you have made a backup of the system disk before conversion.

Step 1. Create a bootable USB drive with Windows 10 Media Creation Tool.

Step 2. Change BIOS boot order and boot from the USB drive.

Step 3. Select your language preferences, and click on Next to continue.

Step 4. On the Windows setup page, click Repair your PC.

Step 4. Choose Troubleshoot to get into the Advanced options page.

Step 5. Choose Command Prompt. Then input the following commands one by one and hit Enter after each.

• diskpart
• list disk
• select disk *
• clean
• convert MBR

Then check if the issue that the selected disk is not a fixed MBR disk has been resolved.

Method 2. Switch Boot Mode from UEFI to Legacy BIOS

GPT is associated with UEFI boot mode, while MBR disk is closely related to old legacy BIOS. Switching the UEFI to Legacy might help you solve the issue when a selected disk is not a fixed MBR in Windows 10. Here are the detailed steps.

Step 1. Restart your PC and enter BIOS setting this time. You may press a specific key to enter BIOS.

Step 2. Find and select Secure Boot in the boot menu and use the arrow key to modify it as Disable.

Step 3. Change the boot mode from UEFI to Legacy. Save the changes and reboot your PC.

This should help you fix the issue that the selected disk is not a fixed MBR disk. If not, try the next method.

Method 3. Fix the Boot Manager

If the error occurs along with Windows boot problems, corrupted boot files or BCD data may also need to be repaired.

You can try the following commands from Windows Recovery Environment to repair the boot configuration.

Step 1. Follow steps 1 – 5 in the above part to open Command Prompt.

Step 2. Input the following commands in the Command Prompt window. Hit Enter after each one.

• bootrec /fixmbr
• bootrec /fixboot
• bootrec /rebuildbcd

Step 3. Then exit and reboot your PC.

If these commands do not resolve the boot problem, avoid making further changes to the disk until you have secured your important files.

Some operations, such as formatting or deleting partitions, can cause data loss. If Windows remains unbootable, consider recovering your important files before trying more advanced fixes.

How to Recover Files If You Cannot Boot into Windows

How to recover files if you cannot fix the issue and boot into Windows? MiniTool Partition Wizard can recover data from an unbootable computer. The steps are as follows:

1. On the software’s bootable main interface, click Data Recovery on the top toolbar.
2. Under the Devices section, select the system disk to Scan.
3. After the scanning process is complete, expand Lost Files, and then locate the files you want to recover.
4. Select the checkboxes next to the files you want to recover, and then click Save.
5. In the pop-up window, select another drive to save the recovered files.

With the help of MiniTool Partition Wizard Pro Ultimate, I successfully recovered the files from the computer with the error the selected disk is not a fixed MBR disk.Click to tweet

The Selected Disk Is Not a Fixed MBR Disk FAQ

Conclusion

This post analyzes the error “the selected disk is not a fixed MBR disk DiskPart” and provides 3 approaches to fix this issue. Besides, you can use MiniTool Partition Wizard to recover data from an unbootable computer.

For any questions or problems when using MiniTool Partition Wizard, contact us at [email protected]. We’ll get back to you as soon as possible.