I have also been having this problem since updating to 2014 (now 2014.9.0.2007 on Win 7 Pro x64 Thunderbird 24.1.0), and now, unless I uncheck "Scan SSL Connections" in Settings>Active Protection>Mail Shield (the other three Main items are checked) I can't get mail. And Avast shows no mail scanning in Statistics.
In my attempts to get rid of the pop up error, I tried to delete the Avast mail certificate but it keeps telling me there already is one (from 3/13). Just now I looked under the Authorities tab and the Avast entry was gone. I reimported it (and see that also says 3/13), and restarted TB (now there don't seem to be any Server entries for Avast in there now).
The same "avast! Mail Shield encountered a problem with the secure connection to your mail server. You may need to configure the SSL scan feature manually..." came up, as well as the TB "Add Security Exception popups, in this case for imap.googlemail.com:993 (8 accounts), imap.gmail.com:993, pod51000.outlook.com:993, pop.att.yahoo.com:995 (5 accounts). All server connections are set as SSL/TLS.
I cannot get/receive mail unless I deselect the Avast SSL Scanning, and it looks like none of the mail is scanned that way, according to the statistics. Can somebody please tell me how to configure TB and Avast to work together so my mail is scanned.
try the following steps (to be sure):
1) if possible (i.e., if you are using an IMAP e-mail account, like gmail) perform a clean uninstall of Thunderbird
(a) "Control Panel > Programs > Uninstall" and Choose Thunderbird
(b) afterwards, use CCleaner (http://www.piriform.com/ccleaner
) to remove any remnants
(c) Start > type %AppData% (and press Enter). A folder named "Roaming" will appear in Windows Explorer. Delete any Thunderbird related folder. Do the same with folders
"Local" and "Local flow", which belong to the same folder three as "Roaming"
(d) restart WindowsNOTE
: Regarding step (c), you should be very
careful -especially if you are also using Firefox
2) Then install Thunderbird again. After having your e-mail account set, do the following
(a) In Thunderbird: "Options > Security > Anti-Virus tab", the single option must be checked
(b) In Avast!(*): "Settings > Active Protection >" choose "Mail Shield", click on "Settings (i.e., Mail Shield Settings) > SSL Scanning" and make sure that "Scan SSL connections"
is checked. Then chose "Export Certificate" (which will produce a certificate with .der -instead of .cer- format
(c) Import it to Thunderbird: "Option > Advanced > Certificates > View Certificates > Authorities > Import". Make sure that in the tab "Servers" (next to "Authorities") there is
nothing related neither to Avast! nor to any recent certificate, which was added as an exception.
Hopefully, these will help...
(*) there is a new version of Avast!, so update