Installing a specific package version on Ubuntu

On Ubuntu and potentially other Debian based distributions, you can check the available versions of a package with the apt show command

apt show -a

Example showing firefox versions

~$ apt show -a firefox
Package: firefox
Version: 87.0+build3-0ubuntu0.20.04.2
Priority: optional
Section: web
Origin: Ubuntu
Maintainer: Ubuntu Mozilla Team <>
 More information

Package: firefox
Version: 75.0+build3-0ubuntu1
Priority: optional
Section: web
Origin: Ubuntu
Maintainer: Ubuntu Mozilla Team <>

To install a specific version, use the version number

sudo apt install firefox=75.0+build3-0ubuntu1

UniFi-Video Service failing to Start

Do note that the UniFi-Video software is no longer supported should be migrated to the UniFi Protect systems.

Running “systemctl status unifi-video” gives the following error.

(unifi-video) checking for and truststore files…

It appears that the error is due to an unsupported version of Java. Installing an older version of Java resolves the issue.

You can check which versions of Java are available with

apt-cache show openjdk-8-jre

The versions that showed up for me were


Installing the last one fixed the issue for now.

sudo apt-get install openjdk-8-jre-headless=8u252-b09-1ubuntu1

Fix White Bar on Windows Explorer in Dark Mode – Windows 10

White bar on Windows Explorer

For some reason you can sometimes have this white bar appear on Windows File Explorer. Fortunately it is an easy fix. Launch Internet Explorer, Yes IE, some of the configuration settings affect both Internet Explorer and Windows File Explorer.

Right click on the Title bar and check the box on Lock the toolbars.

Lock the toolbars to get rid of white bar in Windows File Explorer

Close any open File Explorer windows and relaunch it. It should now be gone.

Windows Explorer without the white bar

Error: Could not create the Java Virtual Machine

Apparently on some versions of Java checking the Java version will give you the following error.

root@local:~# java -v
Unrecognized option: -v
Error: Could not create the Java Virtual Machine.
Error: A fatal exception has occurred. Program will exit.

The issue being the -v or –version options are not recognized. On newer versions of Java it is recognized.

The proper way to do it is -version with only one dash

root@local:~# java -version
openjdk version "1.8.0_252"
OpenJDK Runtime Environment (build 1.8.0_252-8u252-b09-1ubuntu1-b09)
OpenJDK 64-Bit Server VM (build 25.252-b09, mixed mode)

Unity Hub Failing to Launch Unity Project

While trying to launch a project in Unity I kept getting met with, nothing… Click on the project the Hub disappears and nothing happens… Tried uninstalling and reinstalling both Unity and the Unity hub.

I did receive an error similar to the following when trying to launch Unity directly.

windows\system32\msvcp120.dll is either not designed to run on windows or it contains an error

Doing some digging online shows that it has to do with the Visual C++ Redistributable runtime package which can be downloaded here

Unity was back to working normal after installing that.

More information is available at the following link.

Install Element (Matrix Client) on Ubuntu

Installing the Matrix client Element is fairly straight forward on Ubuntu. You should be able to copy and paste the following commands in a terminal.

sudo wget -O /usr/share/keyrings/riot-im-archive-keyring.gpg
echo "deb [signed-by=/usr/share/keyrings/riot-im-archive-keyring.gpg] default main" | sudo tee /etc/apt/sources.list.d/riot-im.list
sudo apt update
sudo apt install element-desktop

fatal: []: UNREACHABLE! => changed=false

Error while attempting to run playbook
ansible-playbook -i inventory/hosts setup.yml --tags=setup-system-user --ask-become-pass

Looks like the above issue is that Ansible is not able to authenticate with the server. By default it looks to try and use ssh keys, but I don’t have any passwordless ssh keys set up for Ansible to use so it fails while attempting to connect. The work around it to make sure you have sshpass installed and then specify –ask-pass to the end of the command.

ansible-playbook -i inventory/hosts setup.yml --tags=setup-system-user --ask-become-pass --ask-pass

When the command runs it’ll ask you for the ssh password and then use that.

[WARNING]: Could not match supplied host pattern, ignoring: matrix_servers

Error while trying to run playbook

If you get the above error when you try running

ansible-playbook -i inventory/hosts setup.yml --tags=setup-system-user

Check and verify that you have [matrix_servers] in your inventory/hosts file

That file should contain the following.

matrix. ansible_host= ansible_ssh_user=root