What happens when you change a dynamic disk to basic

Converting a dynamic disk to basic erases all data on that disk. Windows will not let you do this conversion while keeping your files — the operating system requires you to delete every partition and volume on the disk first, which destroys the data. If you have files you need, back them up to another drive before you start.

A dynamic disk holds volumes that can span multiple physical drives or resize without restarting your computer. A basic disk uses the older partition table system and cannot do either of those things. Most people convert back to basic because they want to use the disk on an older computer, move it to a different system, or because Windows created a dynamic disk by accident when they only needed a basic one.

The conversion itself takes a few minutes and requires administrator access. You will use the Disk Management tool built into Windows, or the command line if you prefer text-based steps.

Key Takeaways

  • Converting a dynamic disk to basic destroys all data on that disk, so back up your files to another drive first.
  • You must delete every partition and volume on the dynamic disk before Windows will let you convert it.
  • Disk Management is the graphical tool most people use, found by typing "diskmgmt.msc" into the Windows search box.
  • The conversion takes a few minutes and requires administrator access to your computer.
  • After conversion, the disk shows as "Basic" in Disk Management and works with older computers and systems that do not support dynamic disks.

Back up your files before you start

Open File Explorer and navigate to the dynamic disk you are converting. Select all folders and files on that disk, right-click, and choose "Copy". Navigate to another drive with enough free space — an external hard drive, USB drive, or another internal drive all work. Right-click in an empty area and choose "Paste". Wait for the copy to finish before moving forward.

If the disk is very large or you have many files, this can take 30 minutes or longer depending on your drive speed and how much data you have. Do not unplug the backup drive or restart your computer while the copy is running.

Open Disk Management and locate your dynamic disk

Press the Windows key and type "diskmgmt.msc" without quotes. Press Enter. A window titled "Disk Management" opens. The top half shows your volumes; the bottom half shows your physical disks. Look for the disk you want to convert — it will have a blue header bar that says "Dynamic" next to the disk number. Write down the disk number (Disk 0, Disk 1, etc.) so you do not convert the wrong one.

If you are not sure which disk is which, look at the size. A 500 GB disk will show as approximately 500 GB in the size column. Match that to the disk you want to convert. If you still are not certain, close Disk Management, open File Explorer, right-click "This PC", choose "Manage", click "Device Manager", expand "Disk drives", and look at the model numbers and sizes there. Then go back to Disk Management.

Delete all volumes on the dynamic disk

In the bottom half of Disk Management, right-click the first volume on your dynamic disk. Choose "Delete Volume". A dialog box asks if you are sure. Click "Yes". Repeat this for every volume on that disk until the disk shows as unallocated space with no volumes listed.

If a volume is locked or in use, Windows will not let you delete it. Close any programs that might be using files on that disk, including cloud storage apps like OneDrive or Dropbox. If the disk contains your Windows system drive (usually C:), you cannot convert it — you would need to boot from a Windows installation disk or recovery drive to do that, which is beyond the scope of this guide.

Convert the disk to basic

In the bottom half of Disk Management, right-click the disk header (the blue bar that says "Dynamic"). Choose "Convert to Basic Disk". A dialog box appears asking if you are sure. Click "Yes". The conversion runs in the background and usually finishes within a few seconds to a minute.

After the conversion completes, the disk header changes from blue to gray and no longer says "Dynamic". The disk now shows as "Basic" in Disk Management. You can close Disk Management.

Verify the conversion and partition the disk if needed

Open Disk Management again and look at the disk you converted. The header should now say "Basic" instead of "Dynamic". The disk shows as unallocated space because you deleted all the volumes. At this point, the disk is blank and ready to use.

If you want to use this disk to store files again, right-click the unallocated space and choose "New Simple Volume". Follow the wizard to create a new partition. You can make it one large partition or split it into multiple smaller ones. After the partition is created and formatted, you can copy your backed-up files back onto it.

Using the command line instead of Disk Management

If you prefer text commands, you can convert a dynamic disk using the command line tool diskpart. Press the Windows key, type "cmd", right-click "Command Prompt", and choose "Run as administrator". Type the following commands in order, pressing Enter after each one:

diskpart (starts the diskpart tool) list disk (shows all your disks; find the number of the dynamic disk) select disk X (replace X with the disk number) clean (deletes all volumes on that disk) convert basic (converts the disk to basic) exit (closes diskpart)

The "clean" command erases everything on the disk, so make absolutely sure you have the right disk number before you type it. If you are not comfortable with the command line, use Disk Management instead — it is safer because you can see which disk you are working on.

Frequently Asked Questions

Can I convert a dynamic disk to basic without losing data?

No. Windows requires you to delete all volumes before the conversion, which destroys the data. You must back up your files to another drive first. After the conversion is complete, you can copy your files back onto the newly formatted basic disk.

What is the difference between a dynamic disk and a basic disk?

A basic disk uses the traditional partition table system and works with all computers and operating systems. A dynamic disk can hold volumes that span multiple physical drives and can be resized without restarting. Most people use basic disks. Dynamic disks are useful for advanced storage setups but are not supported on older systems.

Will I be able to use this disk on another computer after converting it?

Yes. After you convert it to basic and create a new partition, you can move the disk to another Windows computer, Mac, or Linux system. Basic disks are universally supported. Dynamic disks only work on Windows, so converting to basic makes the disk more portable.

What if Disk Management shows my disk as "Foreign"?

A "Foreign" disk is a dynamic disk that was moved from another computer. Right-click it and choose "Import Foreign Disks". This brings the disk online. Then follow the steps above to delete the volumes and convert it to basic.

Can I convert my C: drive from dynamic to basic?

No. Your C: drive is your Windows system drive and cannot be converted while Windows is running. You would need to boot from a Windows installation disk or recovery drive and use the command-line tools there, which requires advanced knowledge. For most people, it is easier to leave the system drive as-is.