Reviewed: 2017-07-14
Product Version:
AhsayOBM / AhsayOBR: 7.13.0.0 to 7.x
OS: Windows
ATTENTION 1st January, 2022: v7 officially End-of-Life [details] ===== Description ===== When performing a granular restore of a Hyper-V guest VM the following error message is shown by AhsayOBM when trying to mount the virtual disk "Failed to list file (The volume does not contain a recognized file system. Please make sure that all required file system drivers are loaded and that the volume is not corrupted)" .
![](http://wiki.ahsay.com/lib/exe/fetch.php?media=public:5255_0.png)
When browsing the virtual disk in AhsayOBM the contents is empty.
![](http://wiki.ahsay.com/lib/exe/fetch.php?media=public:5255_1.png)
===== Cause ===== The drive(s) of the Windows guest VM is encrypted with security software, i.e. BitLocker or other third party security software
===== Resolution ===== To resolve this problem we recommend you either:
- Use RunDirect to power on the guest VM, unlock the drive using the security software to access the files/folders on the drive.
- Restore the guest VM to Hyper-V host and power on the guest, unlock the drive using the security software to access the files/folders on the drive.
===== Keywords ===== Hyper-V, guest VM, granular restore, encrypted volume, BitLocker