How do I get Ubuntu to open folders with Nautilus by default?

Question

After upgrading to Ubuntu 11.10, I once right-clicked on a folder and told it to open the folder with Movie Player ("Open with other application...").

No harm done there, right? Nope, now Ubuntu opens folders with Movie Player instead of Nautilus. If I plug in a thumb drive, Movie Player opens.

If I click on the trash icon... Movie Player! The default action for opening a folder has somehow become Movie Player. Clicking on the "Home Folder" icon still opens Nautilus and opening a folder in Nautilus stays in Nautilus, but other links to folders automatically open Movie Player. How can I change this back?

Answer 1

Answer edited out from the question

Solution was obvious, in Nautilus I select a folder, right click, Open with other application, and pick "Files" which is apparently the name for Nautilus. Now that set the default back... until next time! I guess this is a cautionary tale.

Answer 2

In your home folder go to .local/share/applications/mimeapps.list It is a hidden file. You can unhide it with the following keyboard shortcut: Ctrl + H .

You then need to modify the line inode/directory=movie-player.desktop; or something like that, to inode/directory=nautilus-folder-handler.desktop; and save the file.