Hi, first of all I apologise for my poor English. Second, I try to install Repetier Host on my Udoo board to use it with my 3D printer. In order to install Repetier I must install mono-devel but something went wrong. This is what happens: Code: debian@udoo-debian-hfp:~$ sudo apt-get install mono-devel Reading package lists... Done Building dependency tree Reading state information... Done Some packages could not be installed. This may mean that you have requested an impossible situation or if you are using the unstable distribution that some required packages have not yet been created or been moved out of Incoming. The following information may help to resolve the situation: The following packages have unmet dependencies: mono-devel : Depends: mono-runtime (>= 2.10.1) but it is not installable Depends: libmono-cecil-private-cil (>= 2.6.3) but it is not going to be installed Depends: libmono-codecontracts4.0-cil (>= 1.0) but it is not going to be installed Depends: libmono-compilerservices-symbolwriter4.0-cil (>= 1.0) but it is not going to be installed Depends: libmono-corlib2.0-cil (>= 2.6.3) but it is not going to be installed Depends: libmono-corlib4.0-cil (>= 2.10.1) but it is not going to be installed Depends: libmono-peapi2.0-cil (>= 2.4.2) but it is not going to be installed etc... I look forward for your advice. Regards M.