UFO2Extraterrestrials.com

Ok, my 2nd playthrough of ET Gold, love it! But my alien interrogation tree is jammed. Researched the first 4-5 alien commanders I captured, no problem. But now I can't research any more. If I click on my alien containment facility, it even says "cannot sell this, 4 aliens waiting for interrogation" but no option to do so appears on the science screen. The game acknowledges that I HAVE aliens in captivity, but won't let me "coax" any information out of them. Somebody help! I'm all the way to particle technology (thought if I kept on playing maybe the game would "unjam") and don't want to lose dozens of hours of progress!

Have you tried keeping a copy of the save-file then completely reinstalling the game? All I can think of I'm afraid.

Demolish the alien contaiment room, rebuild it, and try getting some new officers to interrogate, maybe that will help