Got error during installation of Oracle VM VirtualBox Extension Pack

Solution 1:

Virtualbox Extension Pack needs to be installed using root powers according to these bug reports:

• Extpack "Error creating textual authentication agent"
• ExtPack installation failure
• Extpack installation fails

Stack Exchange has the latest installation instructions

LatestVirtualBoxVersion=$(wget -qO - http://download.virtualbox.org/virtualbox/LATEST.TXT) && wget "http://download.virtualbox.org/virtualbox/${LatestVirtualBoxVersion}/Oracle_VM_VirtualBox_Extension_Pack-${LatestVirtualBoxVersion}.vbox-extpack"
https://www.virtualbox.org/download/hashes/${LatestVirtualBoxVersion}/SHA256SUMS
sudo VBoxManage extpack install --replace Oracle_VM_VirtualBox_Extension_Pack-${LatestVirtualBoxVersion}.vbox-extpack
VBoxManage list extpacks

Solution 2:

Any of the following methods will solve the issue:

* GUI way

1. Run VirtualBox as root

    sudo virtualbox
   

2. Go to File→Preferences (or Ctrl+G)

3. Open Extensions tab

4. Click top right button labeled with Add new package.

5. Select downloaded extpack, click Install, agree with license

6. Close VirtualBox

Then open VirtualBox as normal user and repeat steps 2-5 again.

* Terminal way

Install with VBoxManage command:

$ sudo VBoxManage extpack install \
~/Downloads/Oracle_VM_VirtualBox_Extension_Pack-5.1.38.vbox-extpack 
...
Successfully installed "Oracle VM VirtualBox Extension Pack".

As the result it is shown in Preferences→Extensions:

and in terminal:

$ vboxmanage list extpacks
Extension Packs: 1
Pack no. 0:   Oracle VM VirtualBox Extension Pack
Version:      5.1.38
Revision:     122592
Edition:      
Description:  USB 2.0 and USB 3.0 Host Controller, Host Webcam, VirtualBox RDP, PXE ROM, Disk Encryption, NVMe.
VRDE Module:  VBoxVRDP
Usable:       true 
Why unusable: