disable email scanning in your anti virus program and reboot and allow mail to download normally. Turn the AV back on afterwards if you like. BTW what Anti virus are you using. There has been a spike in people having this issue and it is probably time to work out which anti virus is having a cow this time.

I have trend micro which so far has been great. Am still working on finding were to turn off email scanning.

restarting Windows in safe mode with networking and running Thunderbird will have the same result Restart the operating system in '''[http://en.wikipedia.org/wiki/Safe_mode safe mode with Networking]'''. This loads only the very basics needed to start your computer while enabling an Internet connection. Click on your operating system for instructions on how to start in safe mode: [http://windows.microsoft.com/en-us/windows-8/windows-startup-settings-including-safe-mode Windows 8], [http://windows.microsoft.com/en-us/windows/start-computer-safe-mode#start-computer-safe-mode=windows-7 Windows 7], [http://windows.microsoft.com/en-us/windows/start-computer-safe-mode#start-computer-safe-mode=windows-vista Windows Vista], [http://www.microsoft.com/resources/documentation/windows/xp/all/proddocs/en-us/boot_failsafe.mspx?mfr=true" Windows XP], [http://support.apple.com/kb/ht1564 OSX]