We're calling on all EU-based Mozillians with iOS or iPadOS devices to help us monitor Apple’s new browser choice screens. Join the effort to hold Big Tech to account!

Search Support

Avoid support scams. We will never ask you to call or text a phone number or share personal information. Please report suspicious activity using the “Report Abuse” option.

Learn More

Thunderbird hangs when downloading a new message

  • 8 replies
  • 4 have this problem
  • 134 views
  • Last reply by AlanGravers

more options

I get a big lag and TB freezes up whenever it gets a message downloaded, thereby preventing you from typing your emails. It will resume back to normal when the download is finished and whatever you typed will appear all at once. So anything you type while TB is downloading isn't lost; it just doesn't show up on the screen until downloading finishes, about 15-20 seconds later.

I have tried changing the webmail and thunderbird download frequency settings. I've tried starting TB with add-ons disabled. I haven't tried rebuilding files or anything like that, but everything I read says that hasn't made a difference anyway. This problem is directly connected to new mail being downloaded into TB. Happens each time a new email comes in.

Btw, it is an imap connection.

I get a big lag and TB freezes up whenever it gets a message downloaded, thereby preventing you from typing your emails. It will resume back to normal when the download is finished and whatever you typed will appear all at once. So anything you type while TB is downloading isn't lost; it just doesn't show up on the screen until downloading finishes, about 15-20 seconds later. I have tried changing the webmail and thunderbird download frequency settings. I've tried starting TB with add-ons disabled. I haven't tried rebuilding files or anything like that, but everything I read says that hasn't made a difference anyway. This problem is directly connected to new mail being downloaded into TB. Happens each time a new email comes in. Btw, it is an imap connection.
Attached screenshots

Chosen solution

It was a conflict with Windows Defender. Once I turned off real-time protection in that, the problem immediately went away. When I turned it back on, the problem also turned back on.

I had to make a change in the global policy editor to keep it turned off, because it would automatically turn back on after any restart of the PC.

Read this answer in context 👍 1

All Replies (8)

more options

Do you get a 'Not responding' error?

What is your anti-virus software?

more options

no error, just a 20 second lag. anti virus is malwarebytes premium.

more options
more options

Also, is this a gmail account? If not, who is you ISP?

more options

it's world secure email.... also, with windows already up and running in normal mode, I started TB in safe mode and did NOT experience lag. I noticed a tab open with a saved files list. It had lots of entries, so I cleared that list. When I restarted TB in normal mode, I also did NOT experience any lag.

more options

Chosen Solution

It was a conflict with Windows Defender. Once I turned off real-time protection in that, the problem immediately went away. When I turned it back on, the problem also turned back on.

I had to make a change in the global policy editor to keep it turned off, because it would automatically turn back on after any restart of the PC.

more options
Once I turned off real-time protection in that, the problem immediately went away. ... I had to make a change in the global policy editor to keep it turned off,

It is a very bad idea to turn off real-time protection entirely, but you shouldn't let it scan the Thunderbird profile folder.

more options

I still have real-time from Malwarebytes Pro... they were conflicting with each other.