As Thunderbird by default does not have any backup process, I'm wondering what 'backup' process you are talking about. If you are backing up your profile name folder then Thunderbird should not be running whilst you do this as it may connect with servers. The simple way to backup a profile is to just copy the profile name folder and paste it onto an external device. If you use imap mail accounts then make sure you have synchronised for offline use to get a copy into the profile folders. Pop mail accounts automatically download and store emails in the profile. '''How to manually backup profile name folder.''' In thunderbird * Help > Troubleshooting Information * click on 'Show folder' button a new window opens showing you the contents of your profile name folder. Profile name folder is usually called 'xxxxxxxx.default' where the x's are letters and numbers. * Close thunderbird now - this is important * Go up directory and right click on profile name folder and select 'Copy' * Choose where you want to store it eg: external harddrive * right click and select 'Paste'.