If you have all your emails being scanned or Thunderbird folders scanned on starting Thunderbird then the AV product can cause a slowdown.

Reinstalling Thunderbird should not have made any difference as it is identical, but with AV off it would make a difference.

The slowness was on 2 windows 10 computers and started at the same time after the update to TB 45. I agree the reinstall with Earlybird shouldn't make a difference, but it did. Fixed the issue on both systems. Earlybird works great now with full Avast protection.

The message headers would post right away, but the messages took forever (sometimes not at all) to load. It's all good now.

I have a windows 7 machine and this new update has killed me. it takes forever for messages to load. Any suggestions

I use Avast Anti Virus, so I questioned their tech support. This is the response/solution, and it worked perfect.

You have to repair the Avast Program and update it as well. Give it a try and do let us know the outcome.

To repair, Open the control panel->Programs->Programs and Features->Right click on Avast->Click uninstall/change->click repair.

Restart the computer after the repair.

Now update the program by Opening the Avast program->Settings->update->click update on both " virus definition and programs"

Like richborn16, the new update has made loading message excruciatingly slow, and most loads are preceded by a "Thunderbird (Not Responding)" message. I'm running Windows 7, and version 51.1.1 (32-bit). I never noticed the 32-bit part previously - most everything else I run is 64-bit. The only protection I run is from MawareBytes.

The stalling is really intolerable. Is there a way to revert to the prior version?

Hi: The way I fixed it was to delete Thunderbird and then re-install a new version. That seems to have done the trick. All of the emails came back, etc. which was my concern. Otherwise, like you, I could not have used the program. And I, too, have Windows 7 Pro.

Also, while this posting is fine, it would be nice if there was a customer service number to call to assist with these issues. Would save us all a lot of heartache and high blood pressure.

richborn16 said

Hi: The way I fixed it was to delete Thunderbird and then re-install a new version. That seems to have done the trick. All of the emails came back, etc. which was my concern. Otherwise, like you, I could not have used the program. And I, too, have Windows 7 Pro.

I did that, and while it's better, it's still slower than it used to be before the update, and I still sometimes get the "Thunderbird Not Responding" message. I'm really pissed off about this. Why don't Mozilla employees weigh in on these issues, instead of letting other users carry all the freight?

In my environment, the solution is to disable "LookOut (fix version)".

Hi! Windows 8.1 and TB 52.3.0 I was wanting to apply the correction that was recommended by uninstalling Avast. I do not have AVAST on my PC Thanks for your support. Regards Redstart