Update: has spontaneous begun working again . . .

The Thunderbird program update did not cause the problem, but the update triggered the problem which is caused by something else.

The first thing to look at is the security software on the computer. Both the firewall and antivirus software recognized and allowed the previous version of Thunderbird, but may be confused by the new version.

It is recommended that e-mail scanning be disabled in antivirus programs, because antivirus programs already automatically scans stuff when it is accessed. So e-mail scanning is an unnecessary duplication, and that e-mail scanning itself can cause problems.

So disable e-mail scanning in your antivirus program. If the issue remains, then check to make sure that your firewall is allowing Thunderbird.

I did check the firewall etc. For the record, I'm using Norton, and it's set to explicitly allow thunderbird pass-thru in both directions.

Windows firewall is disabled.

There was spontaneous restart of email downloading and I can't account for it--there was no download for 14 hours. What I didn't change was Norton. I did restart thunderbird 4 or 5 times. I'm hoping it continues to work.

elektraum said

I did check the firewall etc. For the record, I'm using Norton, and it's set to explicitly allow thunderbird pass-thru in both directions.

Norton has particular problems with their firewall. In this case it would have been set to explicitly allow 45.6. Without it's update from Symantec, or you explicitly allowing the new version it blocks 45.7. It gets it's marching orders from home and suddenly things start working again and you the user report as you have done a miraculous cure and are left with a sour taste in your mouth about the reliability of Thunderbird updates.

I have seen this exact same scenario thousands of times on this forum, and personally I am tired of Norton making Thunderbird look bad on every single point release. I did try to reach out to them at one point to try and fix this so it did not happen, just as I reached out to them looking to do something about them deleting the entire inbox every-time they thought they found a virus in an attachment. As you may be aware, Norton still deletes whole inbox folders and still stops getting mail.

Please be aware that Norton email scanning only works with non encrypted connections to pop mail accounts. All other email on encrypted connections (yahoo,gmail, outlook/hotmail and most ISP's) is not scanned.

The recent update to 52.1.1 has (again) caused Thunderbird to stop downloading emails (POP3).....my gmail accounts work fine, but my Comcast accounts wil not download. Worked fine prior to the update. I tried all the solutions proffered above without success. Can you tell me what settings I can change in Config editor to get it working again? I NEED my email, if I can't get it working soon, i will have to dump Thunderbird for another client and I REALLY don't want to.....HELP!!!!!!