Retrieving Orphaned .avhdx Files in Hyper-V with No Corresponding Checkpoints

Retrieving Orphaned .avhdx Files in Hyper-V: No Corresponding Checkpoints

In the world of virtualization, Microsoft's Hyper-V is a popular choice for creating and managing virtual machines. When working with Hyper-V, you might encounter an issue where .avhdx files appear without corresponding checkpoints. This article will guide you through the process of retrieving and managing orphaned .avhdx files in a Hyper-V environment.

Understanding .avhdx Files and Checkpoints

Before diving into the issue, it's essential to understand the relationship between .avhdx files and checkpoints. A checkpoint is a snapshot of a virtual machine's state at a particular point in time. When a checkpoint is created, Hyper-V generates an .avhdx file, which contains the differences between the current state of the virtual hard disk and the state at the time of the checkpoint. These .avhdx files are linked to their respective checkpoints and are automatically managed by Hyper-V.

Identifying Orphaned .avhdx Files

Orphaned .avhdx files are those that are not associated with a valid checkpoint. To identify orphaned .avhdx files, navigate to the folder containing virtual hard disk files, typically located at C:\Users\Public\Documents\Hyper-V\Virtual hard disks.

In this folder, look for .avhdx files that do not have a corresponding .vhd or .vhdx file with the same name and a "_" prefix, followed by a timestamp. For example, a valid pair would be myvm.vhd and myvm_2022-03-01T12-00-00.avhdx.

Retrieving Orphaned .avhdx Files

To retrieve orphaned .avhdx files, you can either create a new checkpoint or merge the orphaned file with the base virtual hard disk. Before proceeding, ensure you have a backup of your virtual machine to prevent data loss.

Creating a New Checkpoint

To create a new checkpoint, open the Hyper-V Manager, select the affected virtual machine, and click on Checkpoint in the right-hand Actions pane. Hyper-V will create a new checkpoint and associate the orphaned .avhdx file with it.

Merging the Orphaned File

To merge the orphaned .avhdx file with the base virtual hard disk, follow these steps:

1. Shut down the virtual machine.
2. In the Hyper-V Manager, right-click on the virtual hard disk and select Edit Disk.
3. In the Edit Virtual Hard Disk Wizard, select Merge and click Next.
4. Choose the orphaned .avhdx file and click Next.
5. Select the base virtual hard disk and click Next.
6. Confirm the merge operation and click Finish.

Preventing Orphaned .avhdx Files

To prevent orphaned .avhdx files from accumulating, it's essential to manage checkpoints regularly. You can do this by merging or deleting unnecessary checkpoints through the Hyper-V Manager or by using PowerShell scripts.

• Orphaned .avhdx files are those not associated with a valid checkpoint.
• Identify orphaned files by checking for unpaired .avhdx files in the Virtual hard disks folder.
• Retrieve orphaned files by creating a new checkpoint or merging the orphaned file with the base virtual hard disk.
• Manage checkpoints regularly to prevent orphaned .avhdx files from accumulating.

References

• Hyper-V: Checkpoints
• Merge-VHD
• Orphaned .avhdx files after deleting checkpoints