Installed an updated Thunderbird, and now it want to open attachments with "System Handler" and I do not know what that is and it does not recognize my installed applications to open applications. It does not fined LibreOffice, Evince, Image viewer, gThumb and so on. None of my applications. That means I can not open any attachments to Thunderbird, I can only save them in the file type they come in such as .xls. How do I get rid of System Handler and have Thunderbird use my resident applications.