do you take note of what you are allowing to provide remote content?

Locations not email addresses is what the "allow all" option is about, like allowing images from facebook. The last option in the list is the actual email address. If you want to allow content for that email address, that is the correct item to select, not allow 5 URLs that you my never every see again.

Thanks Matt. From the Mozilla support article: "Note however, that email addresses are easily spoofable in contrast to websites that serve remote content. As long as the network is not compromised, it is much more difficult to spoof content than email addresses." So it's safer to allow content from the (non-spoofable, trustworthy) websites that source the emails than the (spoofable) addresses. The problem appears to be that the list of 'trusted' sites (whether addresses or URLs) is just not getting stashed away anywhere. The 'display' permission lasts for the length of time I have Thunderbird open but doesn't persist after it's closed.

re : open the dialogue and generally select 'Always display from all x above'. The problem appears to be that the list of 'trusted' sites (whether addresses or URLs) is just not getting stashed away anywhere.

After selecting 'Always display from all x above'. Do you see those selected websites in this location: 'Menu icon' > 'Options' > 'Options' > 'Privacy' For 'Mail Contents' - Top right - click on 'Exceptions...' button

Thanks Toad-Hall,

Yup, they're there. Then I close Thunderbird, reopen it, look again and.... pffft! they've gone.

Do you by any chance use something, a program like CCLeaner or another similar product that cleans up old or temp files?

Thanks again Toad-Hall,

Excellent idea! I did have CCleaner. I uninstalled it and tried again but no luck, T-Bird is still making with the magic disappearing exception list.

open the troubleshooting information on the help menu. Click the show button next to the profile folder entry. Close Thunderbird. In the explorer window that opened, locate the file prefs.js. Tight click it.. Is it set to read only? IF so, change that.