End of Mission + Mission Saves Problems

Had my first haven defense where there was a chiron. It ran away eventually. I killed all other pandorans. At that point the Back to Geoscape button wouldn’t work. I alt-tab to end programme. Now the mid-mission saves won’t load. I seem to be able to load the mission start and a previous auto-save on the geoscape just before the haven mission.

Could the chiron trying to escape have anything to do with this? Are the unloadable saves of any use to you?

there’s a “quick save”? What button is that! I have been doing it through the main menu, I wish I knew about the quick save before, so how do you do it? Thanks!

thank you!