https://bugs.winehq.org/show_bug.cgi?id=41510
--- Comment #3 from Austin English austinenglish@gmail.com --- (In reply to brewmanz from comment #0)
I have an app that's failing with err:mscoree:load_mono Could not load Mono into this process
I am attempting to follow https://wiki.winehq.org/Mono which is not very clear.
wine-mono-4.6.3.msi is in /usr/share/wine/mono
I am using a non-default wine location
Put it in ../share/wine/mono of your wine executable.