I'm a long-time user of Thunderbird, and have a whole load of old emails stored in it. Which was fine, until my PC died last month taking my HD with it. No problems, I have backups, but how to apply them to my new rig? As I understand it, all my stuff is stored in these two folders (retrieved from my backup): C:\Users\my-name\AppData\Roaming\Thunderbird\Profiles\yun4892o.default C:\Users\my-name\AppData\Local\Thunderbird\Profiles\yun4892o.default When I install Thunderbird on the new PC, it puts two folders in each of the Profiles folders: km5c5jql.default-release and y3kx2mde.default (the second of which is empty apart from a single times.json file in the Roaming version). I tried removing the profile folders created by the new install and copying the yun4892o ones in instead, but when I launch Thunderbird, it says "Your Thunderbird profile cannot be loaded. It may be missing or inaccessible." So what do I do? Do I perhaps copy some of the contents of the yun4892o folder into one/both of the new folders? I really don't want to lose all my old email!