If you are running operating systems in VirtualBox, it is a good idea to install Guest Additions on the guest system, which will provide a greater degree of compatibility with the virtual hardware so that the guest system can make better use of the available hardware resources. In this description, we will install the Guest Additions package on a system with a Debian 6.1 (Bullseye) KDE desktop environment running in VirtualBox 11.

In this description we will install a Debian 11 (Bullseye) minimal server, which consists of the basic Debian 11 system and some basic program installation and configuration. The server will later serve as a basis for additional server installations. On this page we will install the base system.

VirtualBox can be installed on a variety of operating systems, including all versions of Windows. However, there are still issues with Windows 11. The current version of Virtualbox (6.1) theoretically supports Windows 11, but there are problems during installation. This troubleshooter resolves this issue so that you can install the current latest version of Windows, 11, without any problems.

In this dual boot description, we first install a Windows 11 operating system and then an instance of Ubuntu 21.10 (Impish Indri) Linux. It is installed on a 64-bit UEFI-based machine, where 64-bit systems are mounted on two partitions on a hard disk with a single GPT partitioning scheme. On this page, we'll review the prerequisites and then install Windows 11.

Thanks to virtualization, we have the ability to run another operating system within our computer’s existing operating system. This can be used for a variety of purposes, in this case I will use the free VirtualBox virtualization program for the installation, in which I will install the guest operating systems that are the subject of the tutorials. In this description, in VirtualBox running on a Linux host, I create a guest machine for Linux or Windows operating systems with a graphical desktop environment that requires more hardware resources - and therefore different settings in some places - than the previous version for Linux base systems.

The operating system running on our Debian-based web servers will become obsolete over time, so over time it will be necessary to completely upgrade the distribution. In this description, we will perform a complete upgrade of a Debian 9 (Stretch) web server to Debian 10 (Buster). There are many features on the server that will also be updated. On the first page of this description, we will perform the pre-upgrade steps to prepare your system for a secure upgrade.

If there is a major change to your Debian system - so you don't just need to upgrade one or two sub-versions - you will get an error message during a smooth upgrade:
This must be accepted explicitly before updates for this repository can be applied. See apt-secure (8) manpage for details.
This troubleshooter will fix this.

When you are not using the latest version of a Linux distribution, oddities may arise. For example, in Debian 9, you may receive a "public key not available" (NO_PUBKEY) error message when updating the backports package. We will remedy this problem in this short troubleshooter.

If you frequently use virtual machines with VirtualBox, it is a more convenient and time-saving solution if you do not create and configure a new virtual machine for each installation, but use the existing ones. In some cases, this can cause problems, such as when you try to start your installer in EFI mode, but it does not want to start. In this short little troubleshooter, we will look at how to start ISO installers on EFI mode virtual machines.

Debian 11 (Bullseye) was released on August 2021, 14, and is available in a variety of desktop environments. In this description, we will install the desktop version of KDE Plasma, using the Calamares installer in the Live version, which offers a convenient, clean and simplified installation process. This installation is performed on a 64-bit UEFI machine where the Debian 11 (Bullseye) operating system is mounted on a hard disk with a GPT partitioning scheme.