It turns out, if you both meet the success and failure condition for a quest simultaneously, you fail the quest.
Also, quests appear to only be checked at the end of the turn.

For instance, from my last game:
I got the "Build libraries!" quest. It wanted me to build 7 libraries before Ren era. I already HAD 7 libraries. I was also 1 turn from Education.

Hitting "end turn" I immediately failed the quest for finishing Education, which advances you to the Ren era.
Reloading and switching to another tech for 1 turn caused me to successfully complete the quest because I already had the 7 libraries.
Either way I had to wait until end of turn for the check to complete the quest.

I guess my complaint is that I had completed the quest before the Ren era, so I was a touch annoyed that I didn't receive credit. I guess I can see it going either way when you actually build the 7th library at the same time as finishing the tech.

Is it possible to reverse the order of these checks, and if so, do people think it should be done, or do they not really care? :)

I would have thought you'd get a better response to this in the general Civ4 forums. There are very few regular Mac players here; and even fewer are going to care about this issue; and then you'll be lucky to find one of them who knows enough, and cares enough, to do anything to fix it.

What Alan said. This has nothing specific to Mac civ, but modding in general.

That said... I don't know if this is possible within the XML or even Python. I don't really know enough about events to understand how exposed they are, so maybe you could come up with a Python hack, but I probably couldn't come up with a fix for you, while someone in the Creation forum might.

Wow, how the heck did I do that? :blush: I totally thought I was posting in the Unofficial Patch forum. Thanks for the responses, though! I'll repost there.

(Ah... I visit forums by number, Unofficial Patch is 299, this is 199. Sorry!)