I have Thunderbird as my email system. I have two duplicate files, which seem to have been generated by the Thunderbird system, and which will not move or delete. I have tried your solutions for 'Safe Mode' , starting and disabling Add-ons, deleting the trash folders, and nothing works. They seem to have acquired the same extra file extensions - 0c1df866 - that I did not put on the folder. I have renamed one of the files, and deleted the extra file extension. However the folders will not delete or move. I have tried renaming the duplicate folder, as V2, or 'Duplicate' but I get an error message saying: " The folder could not be renamed. Perhaps the folder is being reparsed, or the new name is not a valid folder name"

So what is going on? I'm concerned in case this issue recurs. How do i fix this permanently? I want EXACT instructions on how to fix this - step by step please.