Edit : Solved it. (methinks)
Mission 50 is won or lost on one mission goal. Complete it and you can advance. Fail it and you have to play again.
The objective is written like this
Schützen sie die Malovolence
-When
--and
---not
----is destroyed
-----GTCv Malovolence
---has-time-elapsed
----1200
The FREDders reading may want to sit and think why that would cause a problem in this mission.
The problem is that if the player completes the mission before the 1200 second delay is up and jumps out the SEXP will evaluate to false meaning you haven't completed the mission.
The problem can be solved fairly simply but I've taken a quick look at the mission and I don't particularly fancy editing a mission in german when all the events are called Event Name (they aren't even numbered! - JUST Event Name for ALL the events!).
Can someone who speaks german look at this message and tell me if it's a succesful return to base message?
Das Omega Team ist mit den Kreuzer ins nächste System geflogen. Wir werden ihnen folgen. Sie können jetzt also ihren Subraumantrieb starten, Captain. Marco Polo, Ende.
If it is I can make the mission rely on that instead of that silly 1200second delay. (of course the other choice is to simply complete the mission stick on 4x time advance and wait till 20 minutes have elapsed
)