MonoDevelop crashes when opening it

You could try a couple of things.

1. Try opening the task manager and going to the processes tab. Find the MonoDevelop process and end the process. Sometimes after using monodevelop for a while and then closing it, I can't open it again and it turns out it's still running and being buggy.

2. If the MonoDevelop process isn't running you could try clearing the AppData for it by going to Users/(user)/Roaming/MonoDevelop-Unity-(version) and delete the items in this folder. WARNING: this will reset your settings in MonoDevelop. Make backups of any highlighting schemes or keybindings that you want, and make note of the settings you want to keep so you can re-apply them.

3. Try re-installing the application, it may be corrupt.

This worked, thank you.