[Note] Ubuntu VirtualBox + VirtualBox Extension Pack

Environment:

Ubuntu 20.04, VirtualBox 6.1.30 r148432

VBox was updated multiple times.

 

Problem:

sudo apt install fails to install VBox Extension Pack 

 

$ sudo apt install virtualbox-ext-pack

Reading package lists... Done
Building dependency tree
Reading state information... Done
The following NEW packages will be installed:
  virtualbox-ext-pack
0 upgraded, 1 newly installed, 0 to remove and 3 not upgraded.
Need to get 10.6 kB of archives.
After this operation, 142 kB of additional disk space will be used.
Get:1 http://us.archive.ubuntu.com/ubuntu focal-updates/multiverse amd64 virtualbox-ext-pack all 6.1.26-2~ubuntu1.20.04.1 [10.6 kB]
 

...omit....

Progress state: NS_ERROR_FAILURE
VBoxManage: error: Failed to install "/usr/share/virtualbox-ext-pack/Oracle_VM_VirtualBox_Extension_Pack-6.1.26.vbox-extpack"
VBoxManage: error: VBoxExtPackRegister returned VERR_VERSION_MISMATCH, pReg=0000000000000000 ErrInfo='Helper version mismatch - expected 0x3 got 0x30000'
VBoxManage: error: Details: code NS_ERROR_FAILURE (0x80004005), component ExtPackManagerWrap, interface IExtPackManager
VBoxManage: error: Context: "RTEXITCODE handleExtPack(HandlerArg*)" at line 1424 of file VBoxManageMisc.cpp
Installation error: License key incorrect or unknown problem during installation.
dpkg: error processing package virtualbox-ext-pack (--configure):
 installed virtualbox-ext-pack package post-installation script subprocess returned error exit status 1
Errors were encountered while processing:
 virtualbox-ext-pack
E: Sub-process /usr/bin/dpkg returned an error code (1)

Fix:

1. Make sure all VMs are closed.
   
2. Open http://download.virtualbox.org/virtualbox/6.1.30/
3. (firefox was used) Click on Oracle_VM_VirtualBox_Extension_Pack-6.1.30.vbox-extpack
4. It'll ask to open with Oracle VM VirtualBox - click Ok.
5. Check: open VBox Manager -> File -> Preferences -> Extensions