Ubuntu: VirtualBox fails to start machine after installing extensions


I just added extension pack and my Windows machines won't start. This is the error I get:

Failed to open a session for the virtual machine Windoze 7.

The device helper structure version has changed.

If you have upgraded VirtualBox recently, please make sure you have terminated all VMs and upgraded any extension packs. If this error persists, try re-installing VirtualBox. (VERR_PDM_DEVHLPR3_VERSION_MISMATCH).

Result Code: NS_ERROR_FAILURE (0x80004005) Component: Console  Interface: IConsole {db7ab4ca-2a3f-4183-9243-c1208da92392}  

I really don't want to re-install VB all over again, so I am hoping to find another solution. I tried some of the other suggested solutions but they didn't work for me. How can I fix this?



Yes, other answers are right: you have a extension-virtualbox mismatch. However, there is a better way, a more Ubuntu way, to solve this using the distro's own installer which is packaged as virtualbox-ext-pack and found in the multiverse.

  1. If the multiverse is not enabled, enable the multiverse.
  2. Close out of VirtualBox.
  3. In the terminal, run sudo apt-get install virtualbox-ext-pack

if for any reason that's already installed and you want to have reinstalled (thus guaranteeing you fix all the problem).

sudo apt-get --reinstall install virtualbox-ext-pack  


The version of extension-pack MUST match the VirtualBox version.

To know your Virtualbox version, open Virtualbox, go to 'help' menu and click on 'about'.

The solution I would recommend is installing the latest version of VirtualBox.

  1. Download the latest .deb file for Ubuntu from here:

  2. Double click on the downloaded .deb file. It will bring-up Software Centre.

  3. Click on the Upgrade button to install the latest version.


As it has been already stated

The version of extension-pack MUST match the VirtualBox version.

But you don't need to install the latest version of VirtualBox - you just need to install matching extension pack.

You can find all older VirtualBox releases (and corresponding extension packs) at https://www.virtualbox.org/wiki/Download_Old_Builds - just download extension pack that strictly matches your currently installed VirtualBox. After you locate your major build number, click on

Extension Pack  All Platforms  

to download the appropriate extension pack.


For VirtualBox Version: 5.0.2-102096~Ubuntu~trusty (I have it installed on Mint Rosa 64 Cinnamon 17.3)

1) in VirtualBox Manager:

file / preferences / extensions

  • remove the offending ext pack

2) download the right ext pack

from http://download.virtualbox.org/virtualbox

  • click on your version
  • download the extension pack (right-click, save link..)

3) in VirtualBox Manager

file / preferences / extensions

  • add the new ext pack

Note:If u also have question or solution just comment us below or mail us on toontricks1994@gmail.com
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