In this case, it was my lab environment, I have an external SSD which is purely just for my lab. I faced this problem is because my laptop reads the external SSD and apply that drive with a different disk letter.
So at first all my virtual Hard Disk are located in disk letter E, this is their original location.
I have multiple USB and external drives so the laptop tends to have a cache of previous used drive. I recently created a bootable USB for another product and when I try to plug in my lab’s external drive, my laptop apply the driver letter as G, I didn’t notice it until I launch my Hyper-V console, the status of my virtual machines are still showing “Off-critical” for quite a long period, refresh also didn’t work. Thus, this causes unable to boot up my virtual machines.
After some thoughts, I connect one of the virtual machine and see the location/directory of my virtual hard disk and it is pointing to the driver letter E, next I go ahead and launch the file explorer and there my external drive is no longer listed as letter E instead of the letter G.
To resolve this, I launch the “Disk management” console, and change the letter of my external drive from G to E. Head back to my Hyper-V console, my virtual machines are able to boot up and the status “Off-critical” is no longer showing.
Note:
- Do take note that it requires a requires a reboot of your laptop if you were trying to mimic/simulate this issue.
There are other reasons that you could face this issue, it could be corrupted drive, or drive is disconnected.
Sabrina Kay's Blog 