I have a dual boot computer (currently Windows 10 and PCLinuxOS. If I boot into Windows and open email I have to either delete all of the files in this path "Thunderbird/Profiles/xugyydgb.default/cache2/entries/" (that's the Linux path) or go into the properties of the folder and change the owner of the folder to my user name. If I do not do that and boot into Linux and start Thunderbird, I get a messaged indicating that Thunderbird is already running and I need to close existing instance and restart. Thunderbird is not running. I tried logging in as Linux root, but even when I do that I can not delete the files in the folder or take ownership of the folder. The folder shows root as owner, but when I try to delete the files it stops and says I don't have permission. Another interesting thing, if that path has files in it from having Windows open, then Linux will only see my 3 Windows partitions as read only. If I have deleted those file while in Windows, everything works as expected in Linux. I have had the same basic setup (on the same computer) with Windows XP, Windows 7 and PCLinuxOS (not sure of the versions) without any problem until about 4 months ago. I honestly, don't know if this is a Windows, Linux or Thunderbird problem. Any suggestions? Thanks, Roger