I've played for 35 years in 6.43, after dropping my last 6.4 games when I played twice that and never found an alien. Now, there's an updated DB so I assume that if I introduced a problem it was overwritten by the change. When I installed 6.43, I had only the scenario, none of my saves and I deleted that to save space/slowdown.
My game settings are difficulty 50% (I'm not that good), at least two spoilers (can I check?), Star Swarm but no precursors or robots. 1000 systems, of which I've explored 125 and completely mapped more than half. I have, oddly, found Star Swarm in places it seems like I maybe should have found spoilers or random new NPRs (which I either left at 30% or set to 40%). I've found them in three unconnected (so far as I can tell) systems, one is quite far distant and had the only Colony Cost 0 planet I've discovered. I love playing and building, but I'd really like to run into an NPR opponent if I could.
I'm going to start a new game (though the DB is saved in a different directory, so not a true test of the DB I'd been using for corruption, assuming that could explain my situation), with 100 systems, 10 NPRs and 50% NPR generation chance.
In the meantime, any help would be appreciated.