I've just encountered an error that seems caught in an infinite loop. This happened in the Populations and Productions window, Summary tab, when I tried to abandon a recently-conquered colony.
Error title: Error in cmdDelete_Click
Message: Error 3420 wqas generated in DAO. Recordset
Object invalid or no longer set.
I conquered this colony within the last month, but doesn't have a population, so I didn't want to keep it since it has a status of Conquered and my regular colony (with no population) has an Imperial status. The alien colony is listed with race Human, even though it came from an alien population ("Elenteriel"). The alien colony contains: 1 x Ordnance Factory, 1 x Terraforming Factory, 96 x Infrastructure.
After clicking Abandon, and saying Yes to the two confirmations, the above error appears. The error appears to loop infinitely.
Maybe related to two colonies on the same planet for the same race, which seems to have happened because the colony had no population, just defending troops (a few Construction troops and something else, maybe a garrison troop) when I conquered it?
There's another alien population in the same system that I'm going to invade, and the F9 screen (system overview, I think) tells me it has 0 population but has defending ground troops. Looks like the same scenario. I'll make a backup of the database in case it's useful for testing, assuming the db doesn't corrupt.
EDIT: The backup appears not to be useful. Relaunched the game and was able to successfully delete both colonies starting with my original human colony. Reloaded the backup, and was also able to delete both colonies starting with the conquered colony.