Steps to reproduce:
1. Open any project
2. Set external code editor as Visual Studio
3. Create any script
4. Double click to open in VS
5. Before startup finishes, right-click Visual Studio icon and "Force quit"
6. Monodevelop will open and might throw an error

Expected outcome: Once visual studio is forced to quit, nothing happens
Actual outcome: Mono develop tries to pick up the pieces(Opens after VS is closed)

Reproduced on: 5.5.0f3, 5.5.4p1, 5.6.2f1, 2017.1.0b10

Note: Error is thrown in 5.6.2f1 and 2017.1.0b10
"Could not load project '[project name]' with unknown item type '{E097FAD1-6243-4DAD-9C02-E9B9EFC3FFC1}'