Steve -
I just experienced a major bug (v4.30). I ran a 5-day turn update six years into the game, and my homeworld population disappeared. There were no events listed in the Events Update screen, no error messages, but my HW pop with 10 billion people and lots of industry everything else just disappeared.
I cracked the database to see if it still existed, but had been unassigned or transfered to another race and it is gone, apparently deleted. There was nothing in-game that could have done this, no hostiles in system, no combat or anything else for that matter. I don't think anything significant or unusual was slated to happen during that time update either.
Found it!
I am just amazed that I didn't encounter this problem during testing. I have recently rewritten cargo handling so that all forms of cargo can use the same code. The cargo type table now contains references to where everything is stored, such as the PrefabPDCs table or PopComponent table. If everything of a given type is picked up then the associated record in that table is deleted. Unfortunately, some items, such as the mass drivers that Waresky mentioned, are held in the Population table. So when the last item of that type was picked up, the code happily went ahead and deleted the population! Oops! I can't believe I didn't run in this though as I ran a game where I shifted automated mines and mass drivers from a mined out asteroid without a problem. This is possibly another factor at work that makes this rarer than it could be but I don't know what it is. Anyway I have fixed the problem and I will get a new version out later tonight. It will be v4.4 as I have made DB changes related to the CIWS.
EDIT: I just remembered fixing a 'bug' before I released v4.3. I had moved the last of some ship components and the stockpile read 0x Ship Component. So I added the deletion code to prevent that problem - and ending up causing a somwhat larger problem
Steve