A while back I launched a mission to Duna. I completed ejection from the Kerbin system, entered solar orbit, made a second burn to adjust my trajectory, and was pleased to see the patched conics report an intercept with Duna. Satisfied, I returned to the Space Center and flew many more missions here and there, occasionally checking on my rover mission in the Tracking Station - still on-course for intercept, days ticking down, with the ship's situation listed as "escaping the sun," even though it was simply on a simple Homann transfer orbit to Duna.
So, at long last, it was only weeks away from its Duna encounter, so I clicked on the tracking station and switched to the ship, and lo and behold, what do I get?
I get this.
Trying to "quit" back to the Space Center did not actually show me the Space Center - it just showed me the starry skybox. Even quitting to menu and re-entering game just showed me the starry skybox instead of the KSP launch complex, even though the time acceleration bar was present at the bottom. I had to quit and restart the game to fix this, and naturally, when I checked back, my flight (which had been in progress for over 200 days) had vanished. The ship was dead and gone, as if it had never existed.
This is the second time this has happened to me - the first time, (in an older version) it was a manned mission, and it auto-killed all the Kerbals aboard, too. I figured this would've been fixed by now. I figured wrong. I'd like to know what did this, because it is seriously liquiding me off.
The only mod I have installed is Kerbal Engineer, version 1.0.18.0.