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Some users have mentioned that when they want to make a primary partition as active with the DiskPart, they received an error message saying "The selected disk is not a fixed MBR disk. The ACTIVE command can only be used on fixed MBR disk." They have no idea why this message appears and want to know if they could fix this problem.
If you are under the same situation, this article will provide you with what you need. You will know why you see this error message and how to solve it.
The Reason Why The Selected Disk is not A Fixed MBR Disk Arises
Several possibilities would cause this "The selected disk is not a fixed MBR disk" problem. We list the most common two reasons below.
- The partition is formatted as GPT.
The active command only works on BIOS/MBR system. When the partition is GPT and your computer is installing a system in UFEI mode, the computer would have trouble recognizing the active command.
- Boot manager problem.
It can also lead to the error message if the computer is booting in a wrong way. You can solve the problem by fixing the boot manager.
If you are confused about what MBR and GPT are, you can refer to the article about MBR vs GPT to get more information.
How to Fix "The selected disk is not a fixed MBR disk"
Now you know the reasons that lead to the error message, you can fix this problem with the solutions introduced below.
Method 1. Convert GPT to MBR
Since the active command only works on a BIOS/MBR system, converting the partition from GPT to MBR could solve your problem. You can choose DiskPart Command Prompt and Computer Management on your computer to conduct the conversion. But both of the two methods will require you to delete volume first, which means these methods are involved in data deletion.
So we recommend you to choose a third-party partition manager - EaseUS Partition Master to fix "The selected disk is not a fixed MBR disk" without data loss. This tool supports users in resizing partitions, converting partitions from MBR to GPT or vice versa, deleting partitions in Windows, etc.
Please download and launch the software on your computer and follow the steps below to convert GPT to MBR.
- Click "Disk Converter" on the left menu. Select "Convert GPT to MBR" and click "Next" to continue.
- Select the GPT disk that you want to convert and click "Convert".
- Wait for the process completes.
Method 2. Fix Boot Manager
This method needs your Windows installation drive. If you can find the installation drive or DVD, follow the steps below to fix the Boot Manager.
Step 1. Boot your computer from the installation drive.
Step 2. Choose "Repair your computer" from the welcome screen.
Step 3. Head to Troubleshoot > Command Prompt.
Step 4. Type the following command:
- FixMbr bootrec
- FixBoot bootrec
- ScanOs bootrec
And press "Enter" after each command.
Step 5. Wait until the operation is finished, remove the installation drive from your computer.
Step 6. Type exit and press the "Enter" button.
Now restart your computer to check if it can boot properly, and check if the selected disk is not a fixed MBR disk error message is still exists.
The Bottom Line
This "The selected disk is not a fixed MBR disk" problem happens mainly because of the conflict of MBR and GPT partition on your computer. Once you have understood the difference between MBR and GPT, you will know how to solve this kind of problem. EaseUS Partition Master is your best choice to manage your partition. With this tool, you can clone, format, and merge partitions without data loss.
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About the Author
Daisy is the Senior editor of the writing team for EaseUS. She has been working in EaseUS for over ten years, starting from a technical writer to a team leader of the content group. As a professional author for over 10 years, she writes a lot to help people overcome their tech troubles.
Written by Tracy King
Tracy joined in EaseUS in 2013 and has been working with EaseUS content team for over 10 years. Being enthusiastic in computing and technology, she writes tech how-to articles and share technical solutions to resolve Windows & Mac data recovery, data backup, partition management, data transfer, Windows update issues, etc.
I love that the changes you make with EaseUS Partition Master Free aren't immediately applied to the disks. It makes it way easier to play out what will happen after you've made all the changes. I also think the overall look and feel of EaseUS Partition Master Free makes whatever you're doing with your computer's partitions easy. Read More
Partition Master Free can Resize, Move, Merge, Migrate, and Copy disks or partitions; convert to local, change label, defragment, check and explore partition; and much more. A premium upgrade adds free tech support and the ability to resize dynamic volumes. Read More
It won't hot image your drives or align them, but since it's coupled with a partition manager, it allows you do perform many tasks at once, instead of just cloning drives. You can move partitions around, resize them, defragment, and more, along with the other tools you'd expect from a cloning tool. Read More
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