This is an extremely trivial guide – but when installing Proxmox for the first time I would have needed a guide like it.
As default, Proxmox is set to update against their paid enterprise repositories – but without a subscription you have no access to them. So what you have to do is remove the enterprise repository and add the free equivalent. You do this by first deleting the following file.
Then we add “deb http://download.proxmox.com/debian/pve buster pve-no-subscription” to the file /etc/apt/sources.list.
deb http://ftp.se.debian.org/debian buster main contrib deb http://ftp.se.debian.org/debian buster-updates main contrib # Add the line below! deb http://download.proxmox.com/debian/pve buster pve-no-subscription # security updates deb http://security.debian.org buster/updates main contrib
You should now be able to update your server and begin your virtualization adventure.