Yes, as a matter of fact I did that before starting the game that showed the problem.  It said that one file was "corrupted" and would be downloaded, which it did.  When I started the game I found that all of my saved options had been reset to the default, so I'm thinking that the prefs.ini file is the one that was "corrupted".  But that's a separate problem.

Anyway, corrupted files are not the cause of the tech tree problem.

Out of curiosity, I just checked this, though I'd validated immediately after patching. Found one file missing, and watching the game start up, it was indeed the pref file that is being replaced.

One thing I haven't been doing is loading a game from within the game, and after I ctrl-N and find a start location, I also exit and restart the game.

This problem usually happens to me every playing session. I sometimes occurs on reloading the game. It always occurs when I play 2+hours at a time. The names disappearing on the tech window is always a precursor to the game becoming sluggish and the UI disappearing all together. I figured it's just a memory leak and kept on truckin'!

When this occurs, I just save the game, close the game, then launch the game again, load my game and the issue is gone for another 2+ hours. I don't think any save game files will show anything because relaunching the game with the save always get the issue to disappear for a while.

Just bought the game and since I don't think I need to make a new thread about it I'll ask here - what exactly does CTRL+N do? I checked the net and all I can think of this is about adding gildar, but isn't that CTRL+M?

Reloads the game with the same settings but generates a new map. Especially useful for randomly generated maps.

We have a fix for this issue in 0.87.

Thanks, it seems you do.  I've tried multiple control-Ns, and loading a save from within a save, and can't get the problem to occur.

Woot!  This will make Sarah very happy, it was a very difficult bug to track down.

Tell her she can have the weekend off!