The package mono-dbg should be installed to get debugging symbols for framework libraries - allowing you to get line numbers in stack traces. The package mono-complete should be installed to install everything - this should cover most cases of 'assembly not found' errors. The package mono-devel should be installed to compile code. Sudo apt install apt-transport-https ca-certificatesĮcho 'deb vs-xenial main' | sudo tee /etc/apt//mono-official-vs.list Sudo apt update Ubuntu 18.04 (i386, amd64, armhf, arm64, ppc64el) sudo apt install gnupg ca-certificatesĮcho 'deb vs-bionic main' | sudo tee /etc/apt//mono-official-vs.list Sudo apt-key adv -keyserver hkp://:80 -recv-keys 3FA7E0328081BFF6A14DA29AA6A19B38D3D831EFĮcho 'deb vs-focal main' | sudo tee /etc/apt//mono-official-vs.list Ubuntu 20.04 (amd64, armhf, arm64, ppc64el) sudo apt install gnupg ca-certificates Note: the packages should work on newer Ubuntu versions too but we only test the ones listed below. The package repository hosts the packages you need, add it with the following commands.