VM will not boot up after a disk resizing.

Discussions about using Linux guests in VirtualBox.
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cfdancer0316
Posts: 1
Joined: 22. Sep 2021, 00:12

VM will not boot up after a disk resizing.

Post by cfdancer0316 »

First off, I'd like to begin by posting a disclaimer that I am a total VM (and subsequently Virtual Box) noob. I know the extreme basics as I just started working with them last year for school. So if I mess up any lingo or go about posting for help all wrong, I sincerely apologize.

While working on a lab for one of my classes, I ran out of space on the VHD. My idiot self went to the virtual media manager and increased it from 10 GB to 20 GB. Now when I boot up my VM, it just stalls on a black screen. I really need some help, is there a way I can get out of this without losing my work? What can I do to fix this?

Some details:

- My host is a Windows 10 machine
- My guest/VM is running 64-bit Ubuntu

Reply with any more information that would be needed, I am quite in a pickle. Like I said, I'm a complete novice and am clueless.
scottgus1
Site Moderator
Posts: 20965
Joined: 30. Dec 2009, 20:14
Primary OS: MS Windows 10
VBox Version: PUEL
Guest OSses: Windows, Linux

Re: VM will not boot up after a disk resizing.

Post by scottgus1 »

The running out of disk space is known to black-screen Ubuntu, on physical PCs as well as VMs. The Ubuntu desktop won't load if there is insufficient disk space.

After you increase the disk size in Virtualbox, you have to increase the partition size inside the VM. Then you log into the VM OS text-only, not starting a desktop GUI. Delete some files (I don't know how many MB) then the desktop will start.
schluk5
Posts: 3
Joined: 23. Feb 2022, 17:31

Re: VM will not boot up after a disk resizing.

Post by schluk5 »

Running virtualbox on mac os.
have resized the encrypted disc of an ubuntu vm only using the slider in the virtual media manager. Increasing it from 10GB to 15 GB. Have done nothing else. Now Ubuntu won't start up. You say I would need to increase the partition size inside the VM now - how do I do that, if it would not start?
scottgus1
Site Moderator
Posts: 20965
Joined: 30. Dec 2009, 20:14
Primary OS: MS Windows 10
VBox Version: PUEL
Guest OSses: Windows, Linux

Re: VM will not boot up after a disk resizing.

Post by scottgus1 »

You could boot your VM with a Gparted ISO and alter the partitions, web-search how to use Gparted.

However, since your VM was encrypted, the normal methods of increasing a disk size may not work, as the actual bits and bytes on the encrypted disk look like white noise to outside programs and may not be interpretable.

I'd suggest restoring the VM's disk file from your backups, decrypting the disk, then increasing the partition, then re-encrypting.
schluk5
Posts: 3
Joined: 23. Feb 2022, 17:31

Re: VM will not boot up after a disk resizing.

Post by schluk5 »

tried Gparted from and ISO and increased partition.
Now the machine starts as before.
Can I do some checks, if I broke anything? What would recommend?
scottgus1
Site Moderator
Posts: 20965
Joined: 30. Dec 2009, 20:14
Primary OS: MS Windows 10
VBox Version: PUEL
Guest OSses: Windows, Linux

Re: VM will not boot up after a disk resizing.

Post by scottgus1 »

schluk5 wrote:tried Gparted from and ISO and increased partition.
Now the machine starts as before.
That's great news! I thought the VM was toast, honestly, because of the encryption.
schluk5 wrote:Can I do some checks, if I broke anything?
Not through any Virtualbox processes. A comparison of data to your backed-up data would confirm stuff. Altering a partition doesn't theoretically change the data in the partition. It should only change the partition borders.
schluk5
Posts: 3
Joined: 23. Feb 2022, 17:31

Re: VM will not boot up after a disk resizing.

Post by schluk5 »

created an artificial file of 3GB which would have not fitted in the 10GB version and it worked fine. So at least the additional extra space of 5GB seems to be available.
anything else I could/should do?
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