I installed the software but it didn't run at all, after few seconds the program disappeared from screen. I installed the Mono-complete package, re-installed the Repetier package, but still no luck. I downloaded the Repetier packages from the official site, both the appimage and the installable program. Again no luck. After various attempt I installed the software via terminal and noticed that there was an alert saying that the program could not enter the /HOME/"user-name"/.mono folder. I checked it and noticed that the specified folder was owned by root (I don't know why, my mistake installing it or what?), so I changed the owner of the folder and all sub folders and file contained in it, to my "user-name" (put your account name there) and everythig worked like a charme!! I hope this can help, I don't know if the problem was caused by an error I made installing the software the first time or if it is a common issue, I report it hoping it's useful.
Struggled to get it to run after install. Searched google, added other stuff, spent over an hour, run from command line to see that it throws exceptions. Will now uninstall and try something else.