Oops! I forgot what his thread was about.
I doubt that your settings are involved if you're taken offline only intermittently. That sounds more like an ISP issue, although why it should affect only you is curious, but not as curious as the filing problem, which
does seem to be Mail related, affecting only you.
Have you tried a
deeep cache cleaning? It may be worth your while to boot into safe mode and let the OS do its thing.