Review for Copy Folder mod by poiuklh
Rated 5 out of 5 stars
From PortableApps.com I downloaded TB 60.9.1. I can run it from a USB stick and use Copy Folder Mod. I found that if you run the portable version first, it's also possible to then run the version installed on your computer side by side (though without Copy Folder Mod) if you need to see other email folders.
Copy Folder Mod can still be a little finicky and hangs once in awhile, but I'm always able to restart Thunderbird Portable and restart the copy.
To create your own collections, you must have a Mozilla Add-ons account.