I'm unable to properly download files using the default Firefox download manager. The relevant extensions are:
1. Download Status
2. Download Statusbar
3. DownThemAll (although since this doesn't interfere with the default, I don't see what this might have to do. Included for completeness).
Now to the problem:
Firefox shows weird behaviour whenever downloading a file:
1. The download completes, and it keeps scanning the file with an antivirus for indefinite periods (it never ended so far) even with tiny text files.
2. During this period of antivirus checking, if I download another file, the old one gets magically deleted.
I'll disable relevant add-ons, and post back the results.
Update: I just disabled all add-ons. The problem persists. In addition:
1. In the download statusbar, it shows scanning, but the download disappears from the download window, so download history isn't kept. I've verified the settings, there isn't anything that says that it shouldn't save download history.
2. Completed downloads vanish off the list, so download history is useless.
3. When the scanning appears in the statusbar, and I start another download, one of the two is kept in the download list, cannot remember which.
Fortunately, I didn't need to disable that. All the priblems were fixed by deleting download.sqlite in the profiles folder, as described in the first link you gave me. It was essentially useless by now, and not really a loss.