virtualbox.org

I wanted to modify both name and size of an existing dynamically allocated .vdi HD, containing a Windows XP OS with no snapshots attached.
So, following this two links, viewtopic.php?f=7&t=46186 viewtopic.php?f=35&t=50661, I

• released the HD and removed from the list of known media
• created a backup copy of the HD
• resized the HD using

  Code: Select all

  vboxmanage modifymedium disk b221d860-a10a-45bf-bf0b-354985cf3773 --resize 15360

  where b221d860-a10a-45bf-bf0b-354985cf3773 is the UUID of the disk
• renamed the file
• went to the Virtual Machine and added again the renamed and resized file to the list of disks

However, when I tried to boot again the machine, the Fatal Error of the title appeared.
I also tried to use the backup .vdi file, without success.
So, thinking of a problem with the UUID, I tried to clone the new media manager using VirtualBox directly and using the cloned media, but it returns again the Fatal Error.

I'm using VirtualBox 5.0.20. Is there any solution to this problem?
Thanks in advance

EDIT:
I forgot to add a very important point: the hard disk was encrypted! I somehow managed to add again the encrypted password to the .vbox file and now, before the start, it asks me for the password. The password check goes right, but just after it the fatal error appears again.

If an encrypted disk is ever unregistered, the randomly generated decryption key is lost. The decryption key is not the password, the password just protects the decryption key.

If the decryption key is lost then the disk can never be decrypted again. To fix this you need to restore both the .vbox file and the .vdi files from your backup.

I note that both of the links you cite date from before encryption was introduced, in v5. I don't see anything in the second link that would be harmed by encryption - it just wouldn't work (in some cases). The first link is as obsolete as its date might suggest, however I've now added a caveat about encryption.

mpack wrote:If an encrypted disk is ever unregistered, the randomly generated decryption key is lost. The decryption key is not the password, the password just protects the decryption key.

If the decryption key is lost then the disk can never be decrypted again. To fix this you need to restore both the .vbox file and the .vdi files from your backup.

I note that both of the links you cite date from before encryption was introduced, in v5. I don't see anything in the second link that would be harmed by encryption - it just wouldn't work (in some cases). The first link is as obsolete as its date might suggest, however I've now added a caveat about encryption.

Thanks for your time.
Btw, in order to "decrypt" the disk, I've modified the .vbox file copying the CRYPT/KeyId and CRYPT/KeyStore from the other device attached to the same machine. Do you think it could work?

Yes, I think it could work, but that is a total guess since I would never knowingly use encryption for my data, at least not at this global level, since the result of any glitch is of course total and unrecoverable data loss.

mpack wrote:Yes, I think it could work, but that is a total guess since I would never knowingly use encryption for my data, at least not at this global level, since the result of any glitch is of course total and unrecoverable data loss.

Well, obviously it's an experimental machine and the HD contained only the OS, with the data in another encrypted and safe disk.
Btw, as I said, I think that the method above worked, since now VirtualBox shows me a prompt to insert the password; however, after it, the Fatal Error message appeared again.

For now, I simply solved reinstalling the OS on another HD, but it could be nice to know where is the problem and how to solve it.