Managing VirtualBox VDI size for a Linux Guest

If you are just looking to save space on your operating drive, always remember to use the Description box for snapshots and delete those you no longer need.

And if the guest host is Ubuntu, see some good pre-wash steps at

Assuming you are using a dynamic disk you can perform the following steps below save more space:

Check for a dynamic disk VDI
Verify the VDI is a dynamic disk

From within the Linux guest, run the following in a terminal:

dd if=/dev/zero of=/var/tmp/bigemptyfile bs=4096k ; rm /var/tmp/bigemptyfile

It will take some time to complete. Depending on the size of the disk and the amount of empty space, it can be a long time, so be patient.

When the commands complete, shut down the guest.

The next step is to run VBoxManage.exe. First, locate where VirtualBox is installed. This is usually C:\Program Files\Oracle\VirtualBox, though you can also find it by checking the path of the VirtualBox launch icon:

Find the VirtualBox install location from the launch icon properties
Find the VirtualBox install location from the launch icon properties

Open a commend prompt (search for cmd.exe) and cd to where VirtualBox is installed:

cd "C:\Program Files\Oracle\VirtualBox"

Locate and copy the path to the VDI:

Locate and copy the path to the VDI
Then run VBoxManage as follows:
VBoxManage.exe modifymedium disk “[absolute path]” –compact

VBoxManage.exe modifymedium disk "T:\VirtualBoxes\Ubuntu_21.04_withVPN\Ubuntu_VPN_21.04-disk002.vdi " –compact

I also back mine up, which is why I need to reduce the size.

VirtualBox Export Appliance Menu


© Scott S. Nelson

All Work and No Play…Mass Update Your MP3s with Cover Art

Rather than buy a new car to get a dashboard computer, I just bought a tablet and mounted it on my ashtray. For the music, it is easier to see what is playing from cover art, but not all of my MP3s have it. So I went on a search..

I will save you the trials and errors of a half-dozen programs that will run on the latest patch of Windows but require adding the images one-by-one (I have 11,000 songs on the tablet). The only program I found that adds the images automagiclly is MP3 CoverTag. Well, it is supposed to because I read a dozen articles that said it did. Problem is, Microsoft has patched it to death and I could not run it.

I got around the patch issue by doing the following (extra steps added for those that didn’t already have the VMs handy):

  1. Download VirtualBox
  2. Download an old Microsoft-provided VM.
  3. Import the VM into VirtualBox. During the import or before starting it:
    1. Bump the RAM up to at least 2GB
    2. Add a shared folder that auto mounts where you will put your MP3s to update
  4. Start the VM and make sure Windows Update is set to Never Update
  5. Download MP3 CoverTag
  6. Log out and create a snapshot so you can always go back to it the state of an unpatched machine with MP3 CoverTag installed

Now you can run the unpatched VM and MP3 CoverTag will work.


© Scott S. Nelson