Comment 117 for bug 260492

no computer expert, just cut & paste
copy below into terminal
gksudo gedit cat ~/.local/share/applications/mimeapps.list

below list came...

Added Associations]

message/rfc822=gedit.desktop;openoffice.org-writer.desktop;thunderbird.desktop;

application/octet-stream=eog.desktop;

application/vnd.ms-powerpoint=openoffice.org-impress.desktop;openoffice.org-writer.desktop;nautilus-browser.desktop;

application/x-ole-storage=openoffice.org-draw.desktop;

inode/socket=f-spot-view.desktop;

application/x-extension-part=vlc.desktop;

inode/directory=vlc.desktop;nautilus-folder-handler.desktop;transmission.desktop;nautilus-browser.desktop;

application/x-executable=gedit.desktop;

application/x-extension-drive=nautilus-browser.desktop;

application/x-extension-link=nautilus-browser.desktop;

image/png=eog.desktop;f-spot-view.desktop;gimp.desktop;firefox.desktop;nautilus-browser.desktop;

text/x-ldif=gedit.desktop;openoffice.org-writer.desktop;thunderbird.desktop;

after ..
inode/directory=
delete ( vlc.desktop;)
should read..
inode/directory=nautilus-folder-handler.desktop;transmission.desktop;nautilus-browser.desktop;

worked for me!!!!