Some volumes will be lost after converting dynamic disk to basic

Dynamic disks and Basic disks are two different storage types used in Windows operating systems. While Dynamic disks offer advanced features like spanned, striped, and mirrored volumes, they are often less compatible with certain scenarios, such as multi-boot environments or specific home editions of Windows. Consequently, many users decide to revert their storage to the standard Basic disk. However, this process is fraught with risk. A common and distressing scenario users encounter is finding a partition lost after converting dynamic disk to basic.

Why will some volumes be lost after converting dynamic disk to basic?

Understanding the underlying architecture of file systems is crucial to realizing why data disappears during this conversion process. The issue usually stems from the limitations of Windows' built-in tools or the complexity of dynamic volume structures.

The primary reason users experience a partition lost after converting dynamic disk to basic is the destructive nature of the Windows Disk Management tool. Microsoft’s native utility does not support the direct conversion of a dynamic disk with data on it to a basic disk. To perform this operation using Disk Management, you are technically required to delete all volumes on the dynamic disk first, turning it into unallocated space. Only then can you convert it. If a user forces a conversion or uses unreliable command-line inputs without deleting volumes first, the partition table can become corrupted, rendering the partitions invisible or "lost" to the operating system.

Furthermore, dynamic disks support complex volume types like Spanned, Striped (RAID-0), or Mirrored (RAID-1) volumes. These volumes spread data across multiple physical disks or non-contiguous sectors. Basic disks generally require contiguous partitions. When you attempt to convert dynamic disk to basic, if the software used cannot correctly map these complex dynamic structures into the simpler Master Boot Record (MBR) or GUID Partition Table (GPT) format of a basic disk, the volume information is discarded, resulting in lost partitions.

How to fix partition lost after converting a dynamic disk to basic

When you are converting a dynamic disk to basic, it may prompt that some volumes will be lost after converting. And you are not able to proceed to convert the disk. In this case, you need to convert it in a roundabout way. AOMEI Partition Assistant Professional includes a dedicated "Dynamic Disk Converter" feature. This tool allows you to convert dynamic disk to basic directly without deleting volumes.

Before reading the following content, please note that the software doesn’t support to convert a dynamic disk which is larger than 2TB to basic. And Dynamic Disk Converter doesn’t support to convert spanned/stripped/Raid5 volumes to basic partitions directly.

Converting a dynamic disk with spanned/stripped/Raid5 volumes created on, you will get the information like in the screenshot below:

Step 1. Install and launch the program, click the target disk and select "Dynamic Disk Converter".

Step 2. In the next screen, select Method 1 and click "Next” to continue.

Step 3. Check the dynamic disk you want to convert to basic and click Next. Then check the confirmation option and click “Proceed” to execute.

In addition, you can also copy or back up the files in that volume to other location directly, then delete that volume. To back up the files, you can use AOMEI Backupper.

Note: There are only volumes that are marked as simple volumes on the source dynamic disk, but you still have the problem. This will only occur when the simple volume occupies 2 or more slices, like in the screenshot (there are two E on the dynamic disk):

Run Dynamic Disk Manager. Right click the target volume and select Shrink Volume. Drag the bar to shrink the target volume until it only occupies one slice. Click OK.

Before shrinking

After shrinking

Then you can run Dynamic Disk Converter to convert the dynamic disk back to basic. If there are data saved on 2 or more slices of the volume, this method is impractical.

Other Handy Functions of AOMEI Partition Assistant:

Beyond partition recovery and dynamic disk conversion, this software is a comprehensive PC manager:

• OS Migration: Move your Windows installation to a new SSD without reinstalling.

• MBR/GPT Conversion: Convert system disks between MBR and GPT partition styles (essential for Windows 11 upgrades) without data loss.

• App Mover: Free up space on your C drive by moving installed applications to another drive without affecting their functionality.

• Disk Clone: Create exact replicas of your hard drives for backup purposes.

To sum up

The panic associated with a partition lost after converting dynamic disk to basic is understandable, but the situation is rarely permanent. This issue typically arises from the rigid limitations of Windows Disk Management or the complex structure of dynamic volumes, which fail to map to basic partition tables. While native tools require you to destroy data to change disk types, third-party solutions offer a lifeline.

AOMEI Partition Assistant Professional stands out as the authoritative tool for this scenario. Not only can its Partition Recovery Wizard scan and restore lost volumes, but its Dynamic Disk Converter also provides the correct answer to how to convert disk from dynamic to basic safely—without deleting a single file. By keeping this tool in your arsenal, you can manage your storage architecture with confidence and security.