First, the OS X version does not support Armory management of bitcoind, so I'm stuck with the BitcoinQt approach.

Second, I guess I can just wait till the blockchain downloads, and then have Armory build its db afterwards. But is there some reason in principle that Armory cannot recognize incomplete blocks? During normal operation (i.e. after most of the blockchain is downloaded), Bitcoin-Qt is periodically getting new blocks, so there is a short window every 10 minutes when the situation is similar. Also during normal operation, I assume Armory periodically scans for new blocks (after Bitcoin-Qt tells it a new one has arrived), to extend its own database and display fresh data to the user. When it does this, there are probably no new partial blocks yet (because the next one wouldn't come for at least 10 minutes). But there is a small chance that two blocks are found almost simultaneously, right? In which case, right after Bitcoin-Qt tells armory it's ok to update its db, it might start downloading other partial blocks from random peers. So why couldn't the same "missing block data" cause crashes even after the initial bootstrap? Or are there certain state guarantees about ~/.bitcoin/blocks that are satisfied *except* during the initial bootstrap?

Apologies if these are dumb questions, just curious.

Regardless, the documentation (for all versions, but especially OS X since there's no choice) should probably be clarified to inform the user who is manually running bitcoin-qt that they must not run Armory until the blockchain is "fully" downloaded. I did see this on a non-official website about armory, but I assumed it was probably wrong and just a waste of time.