Hyper-V as a virtualization platform is introduced by Microsoft in 2008. The main role of Hyper-V in Windows Server is that it helps users to create a virtualized server environment. For example, virtual switches, or other type of virtual devices, which can directly be added to a virtual machine. Hyper-V is simply used to provide virtualization of hardware where one can manage any type of virtual machine. One can run multiple operating system on a single computer in isolation from each other. This technology basically used to improve and enhance the efficiency of the computing resources and free up space of the hardware resources. In addition, it can also be said that Hyper-V is the hybrid or the server hypervisior. Moreover, the Hyper-V stores all its data in virtual hard drive in two different file format i.e. VHD format and VHDX format.
The Hypervisor or Virtual Machine Monitor (VMM) is a piece of application, code or a hardware, which let users work on a virtual machines in a way that they are working on a physical machine. In other words, it can also be said that it allows multiple virtual machines to share single hardware. Using this, multiple operating system at the same time shares a single host along with its hardware. In addition, a hypervisor handles the requests by virtual machines in order to access the hardware resources (such as RAM, CPU etc.) and act as an independent system. However, the Hypervisor is divided into two different types, which are:
Also known as Native or Bare Metal hypervisor and works on host hardware directly. It also monitor all operating systems that run on the hypervisor. In addition, it is completely independent of the OS. The common example of type 1 hypervisors are Citrix XenServer, MS Hyper-V, etc.
In Type 2, the hypervisor is first installed on the OS and after that, it supports any other operating system on it. Dissimilar to Type 1, it is totally dependent on the host OS for any operation. However, it run multiple OS at once but does not have direct access to hardware. The common example of type 2 hypervisor is Microsoft VirtualPC, etc.
VHD is a type of file extension used as disk image file format to store all data of a hard drive. VHD generally stands for Virtual Hard Disk uses .vhd file type to store data on the virtual environment in same way as on hard drive. In addition, there are basically two types of VHD file and both of them are mentioned below:
VHDX is another Hyper-V virtual hard disk (VHD) format used by Windows Server 2012. It is basically an extended form of VHD file with some new enhancement. For example, improve performance, prevent corruption and a maximum storage capacity of 64 TB. However, its work exactly same as the physical hard disk and its main concerned is on the guest operating system.
There are many different factors that can badly affect the Hyper-V VHD and VHDX file and all of them are discussed below:
The most common reason behind the corrupted VHD file is because of some type of virus attack. However, virus infection in a computer system can badly affect the complete system and to the already downloaded software on the system. It can be possible that while downloaded something from the internet, a user has downloaded some malware on the local machine.
It can be due to some wrong command or action through which application get infected or may crashed on the spot. Or it can also be due to some small errors in a Virtual machine, which results in the system crash or corruption in VHD file.
VHD is basically like a physical hard disk that has the ability to get saved on the host system. However, if any of the storage device on the system gets damaged or failed, then it mat leads to inaccessibility of files that are stored on the storage device and VHD file as well.
Software failure due to any reason like because of human mistakes, also leads to crashed Hyper-V or damaged VHD file. It is because the application gets clashed with the already saved data on the system. It can also be due to some internal damage in VHD file also.
If a user connects his/her system with the already infected or corrupted external drive like SCSI, flash drive, or SATA IDE, etc., then it may also leads to an issue in a VHD or VHDX file.
Suddenly or forcefully shut down of any running system may cause bad damage to the all system software & hardware devices really badly. Moreover, improper shutdown of the Virtual Machine can also results corruption in Virtual hard disk (VHD) file or VHDX file.
Deletion or removal of any saved files accidentally, removing system registry, improper disk management, forcefully shutdown are some problems that occurs due to human mistakes. However, it can corrupt already saved VHD file also in the Virtual Machine.
In order to recover damaged .vhd and .vhdx file, there are various methods present and all of them are discussed below:
Initial thing that a user can try is to check the integrity of a VHD or VHDX file that needs to repaired. First of all, a user needs to run a script on Windows PowerShell, which helps in mounting the VHD file into a root folder. After that, one can run a CHKDSK on it. A user needs to run the command given below:
After executing the above commands, run a CHKDSK on the VHD or VHDX file.
Another possible method to repair crashed Hyper-V VHD file is that one can creates a new Virtual Machine. After that, you can add the damaged .vhd to newly created Virtual Server and then compact it. To do the same, follow the steps given below:
Remember: If the original size is 50 GB of VHD in actual and it stores only 10 GB data, then the newly created VHD file will be compacted to 10 GB simultaneously.
When the VHD file is compacted successfully, you can copy the .vhd file to the original back and can try to mount that VHD file.
One can also try the free VHD tool offered by the Microsoft. In addition, the tool has an option to repair VHD/ VHDX file. Therefore, to do the same, download the .exe file, and run the tool as an administrator on the local system by following the command shown below:
VhdTool.exe /repair < BaseVhdFileName> < FirstSnapshotAVhdFileName> [/quiet]
If any of the above method does not works perfectly, then it is advised to switch to a professional solution i.e. Hyper-V VHD repair tool. The software is designed in such a manner that it recover corrupt, dismounted .vhd file or partitions without any issue. It repair both static and dynamic VHD file data of FAT (16, 32) & NTFS file system. In addition, it does not has any file size limitation to repair crashed VHD file. Apart from all this, the tool is compatible with Microsoft Windows Hyper-V, Virtual PC & Virtual Server. The tool is capable enough to recover damaged .vhd file without installing virtual environment. Now, to recover data from corrupt, dismounted, formatted, and reformatted VHD partition using the steps mentioned below:
Working Steps of Hyper V Data Recovery Software