Storage configurations are missing after reboot

[trickme]

Hi,
I have installed oracle virtualbox Version 5.0.14 r105127 on windows 7 running on my laptop.
i installed a couple of centos vms and configured the system, powered off the vms and took snapshots and left for the day with laptop shutdown.
after powering on the laptop, when i tried to power on the vms in virtualbox, i started getting " fatal: could not read from the boot medium! system halted."
i then checked the storage settings and found that the controllers and disks were missing.

Note: these vms were running as linked clones of a master VM which however is still fine.
i have attached the screenshot of the storage configuration missing from the vm.

Please let me know the fix if anyone faced this and have overcome the problem.
thanks.

[mpack]

You say the parent VMs are still present. Are they in the same place? Have you moved the VM, or has Windows, perhaps, reassigned the drive letter?

That said, I would expect VBox to complain clearly about missing media, and the controllers should still be there. I've never seen this before.

[trickme]

Thank you for looking into this.
I verified all of the things that you mentioned.
The parent VM is in its place, and also functional - (i can power it on and login into the guest). i have not moved any VM so far. also, there is no change in drive letter. the filesystem on windows is as is when the vms were first created.
when i navigate on to the filesystem where the vm files are, i see all the disk files intact.
The vbox is not complaining about any missing config.

[mpack]

Do you have a backup of the affected VM? If so you can restore the .vbox file from it. Normally if there is a glitch I would suggest renaming the ".vbox-prev" (VBox's own local backup) file to ".vbox", but in this case I suspect that you'll have run this VM multiple times, so the local backups will be overwritten too.

If this were a vanilla VM then repair would be trivial, but the fact that a differencing scheme is involved makes repair rather tricky.