sounds to me like you moved the data, not copied it. Or tried to copy it while Thunderbird was open. I can not guess which.

Hello, ''<p>dsmith11 [[#question-1327111|said]]</p>'' <blockquote>I was trying to back up Thunderbird. I copied my default profile to my desktop. Now when I open Thunderbird, all of my inbox messages reloaded, like never looked at. All of my folders I've added over the years are gone. Help. </blockquote> Did you back up your data following the steps of this guide? Reference the sections "Backing Up a Profile" and the "Restoring a Profile Backup" to hopefully restore your profile and data. [[Profiles - Where Thunderbird stores your messages and other user data]]