I too have experienced issues with Avast 7.0.1474 preventing Thunderbird 17.0 from downloading email messages from an IMAP server. I get my email just fine when using my Comcast Cable modem internet connections but continually get timeouts from Thunderbird when running on my parent’s 1.5 Mbit ADSL modem. I first changed the timeout settings in Thunderbird but to no avail. Then I opened up all the ports on the router and that didn’t help either.
The solution was to turn off the Mail Shield in Avast for 10 minutes. Thunderbird downloaded all my emails just fine while Avast was disabled. Interestingly, when the 10 minutes are over and the Mail Shield is reactivated, I continue to get my emails. So somewhere a sticky flag got set in Avast or Thunderbird.
I do have a ton of emails in my inbox ( > 31,000). The timeout occurs while “Opening folder INBOX….”. Thunderbird memory footprint is 131 MB.
Details:
Intel Core i7-3610QM CPU 2.3 GHz with 8 GB RAM
CPU usage: 10% Memory Usage 4.37 GB
Windows 7 64 bit
Avast Free Version 7.0.1474
Thunderbird Memory footprint from Task Manager 131 MB
Unread: 3224 (messages)
Total: 31698 (messages)
mail.server.server1.timeout user set integer 29
mailnews.tcptimeout user set integer 200
network.http.connection-timeout user set integer 300
