I recently had to reset my computer to "factory new". I made a complete backup of my hard drive first. I reinstalled Thunderbird onto my machine and downloaded email from my server. I then moved my "back up" files onto Thunderbird. Suddenly, some of my folders have @ signs on them. What does this mean? Who put it there? Why? It seems to effect the use of subfolders and some add-ons refer to them as "special folders" and won't work. Any ideas?