I used to play the discovery mod during 4.86. I then uninstalled freelancer all together and then recently decided to play again on a different computer.
While I can play the mod, whenever I turn off my computer I need to reinstall it because when I try to launch it crashes. It takes a few minutes after clicking on my shortcut to it and then I see nothing but a black screen. All I can do at that point is turn off my computer as it refuses to accept any commands.
I'm running on windows 7 Home premium 64-bit. I can play the mod but it's a bit of an inconvenience to have to reinstall it every time I want to play it after turning my laptop off. I can close the mod and reopen it without any problems. It just crashes if I don't reinstall it after shutting down. I have fully uninstalled and reinstalled freelancer several times and the problem still persists.
You might have some old save files in the Documents\My Games\Freelancer\Accts\SinglePlayer directory. Incompatible saves can cause the game to crash at the menu. Simply rename or delete the said directory if this is the problem.