what happens if you turn off outgoing mail scanning in your anti virus? What is it anyway?

I use Bullguard as AV protection and I can't do what you suggest without turning off the whole program which I'm loathe to do. But I will try it briefly just to see what happens. Do you have any other suggestions in the meantime that maybe the cause?

Thanks

I approached Bullguard for their help and tried everything they suggested but nothing made any difference. Outgoing email is still very slow to clear.

Restart your computer in safe mode with Networking. This loads only the very basics needed to Re start your computer while enabling an Internet connection. Click on your operating system for instructions on how to start in safe mode: Windows 8, Windows 7, Windows Vista, Windows XP, OSX

Did that help?

I did what you suggested and email was delivered in a blink. so obviously there's something in my system or in the Thunderbird set-up putting the brakes on

Thanks Barry

Appears to me that you can disable "Scan e-mail" in Bullguard without affecting the other components, including the real-time background protection:

http://www.bullguard.com/support/product-guides/bullguard-desktop-protection-guides/antivirus/antivirus-settings.aspx

Thank you for your advice which helped me to get to the cause of the problem. All is now working as it should.

Barry

Could you p[lease advise your version of bullguard so I can update our information here https://wiki.mozilla.org/Thunderbird:Testing:Antivirus_Related_Performance_Issues#Bullguard

I have the latest version of Bullguard 15.02.298 Thanks for your help

Barry