One for the internet knowledge bin. For a little while now, Firefox (both 2.0 and the freshly installed 3.0) has been forgetting my downloads. That is, the files are downloaded to my chosen location, but as soon as they're done, they disappear from both the usual Firefox downloads window, and the neat (and very highly recommended) Download Statusbar add-on.
I checked the immediate culprit - the Privacy tab in the preferences has a tick box labelled "Remember what I've downloaded". But that was ticked, so it can't be that. I checked it wasn't the fault of other plugins. Not that either. So I kind of resigned myself to having to skip to the desktop to retrieve my downloads, promising that next time I'd try and figure it out properly.
Anyways, tonight my patience ran out. And it turns out to be very simple - that tick box looked ticked, but given that when I clicked on it first time it stayed ticked, it suggests that really Firefox considered it to not be set.
In summary, for those not paying attention, give it a few clicks to get it in sync, and wa la, downloads back to normal again. Easy.