I’ve been trying to hack monogame on my debian recently. I first installed monodevelop 7.4 using apt, and then installed monogame 3.6. I opened monodevelop without any warning message, however, it reports “create project failed. no access to the given key” when I try to create solutions. Does anyone know what’s going on?
I finally figured out there’s privilege problem in path /etc/mono/registry. But after fixed the problem, I ran into another one - the compiled assembly can’t run from monodevelop, which reports the exe file can’t be located. Never mind, it seems monodevelop+mongame isn’t that mature as I thought. I will transfer to win7 platform and use vs2015+monogame like everybody else.
Nope, there is a bug in MonoDevelop when it comes to opening/creating projects: https://github.com/mono/monodevelop/issues/4040
Also there is a separate bug where MonoDevelop fails to open the correct path when you press on Run/Debug.
In short use either VS Code or Rider if you wanna use C# on Linux, MonoDevelop sucks.
Thanks for the tip! 
Im running a debian-based as well and had the issue, i found out its cause the stupid root requirements i dont know why it installs to a root based dir, but either start MD in root, or find the directory its installed to and change the permissions on the directory and files to allow your user.
Afterwards it doesnt have problems anymore 
EDIT: (I set it a while ago and forgot the exact directory so i didnt originally include it) It should be located at /usr/lib – I dont know exactly if its the same on all Debian based distros so disclamer I use Linux Mint Debian Edition and it may be slightly different path. Make sure to change the WHOLE MonoDevelop folder permissions.