EDIT: Fixed it. Turns out the 'Saved Games/DCS' folder needed to be rebuilt, and apparently that failed to complete after the last update, and the folder wasn't removed upon uninstalling DCS World + all modules. Deleting the aforementioned folder and relaunching DCS World recreated the DCS folder, and fixed the issue!
----------
When I try to view the Mission Planner this is all I get, I can only Alt+Tab to minimise and Alt+F4 brings up 'are you sure you want to quit'?
I tried uninstalling all modules + DCS World, yet this still happens on a fresh download and install of DCS World. Also, when I click 'Create Fast Mission' nothing happens.