And with that, I've now updated the extension to probe for "userstoreIsAvailable" status before making any writes to its USB (FAT) files, which is a flag that goes to 0 whenever it's plugged-in to USB. Concurrent writes to a FAT volume can, as I've experienced, be fatal. So now the extension avoids those at every level. Could be a useful tip for anyone developing extensions of their own, too.
https://github.com/FalconFour/online...92fec8bddcf751