I have a file that is formatted as a .doc, but Nautilus and LibreOffice insists that it is a .txt. Both precise and Ubuntu 12.10 are that way, but Google Docs can convert it (after playing with it).

enter image description here

enter image description here

enter image description here

  • It opens, it just reads it as a text/plain document, not as a MS word doc. Removed the +'s, no difference.
    – jrg
    Aug 24, 2012 at 14:17
  • could you try my edit @jrg . Damn, I need to know the answer :X :X
    – Rinzwind
    Aug 24, 2012 at 14:28
  • @Rinzwind I'm stupid, it's this thing. listarchives.libreoffice.org/global/users/msg22140.html
    – jrg
    Aug 24, 2012 at 14:52

3 Answers 3


To check if 'extension' mime type exist:

grep 'extension' /etc/mime.types

To create new mime type:

  1. Open /etc/mime.types with text-editor(with root privileges)

    gksudo gedit /etc/mime.types

  2. Add extension to /etc/mime.types in following format:

    text/extension extension

For more info click here

  • I did but nautilus doesn't recognize the change Jun 4, 2021 at 20:53

Could be something as simple as a mangled/intentionally changed header. Here's what the MS Word first 2 chunks looks like in a couple of documents I just checked:

D0 CF 11 E0 A1 B1 1A E1

You could MAKE A BACKUP and try changing the first several bytes to that signature and see if it doesn't at least TRY to open as the right thing.

Generally, file can look at this area:
enter image description here
And tell the file-type. If it's detecting it wrong, either it actually is a text file renamed to doc or the header got borked.

  1. In Nautilus, right-click on any file with the desired filetype or extension, choose Properties from the context menu.
  2. In Properties click on the Open With.
  3. Select an application for the given filetype (writer I asssume). All files with the same extension will now be opened with this program by default.

enter image description here

You can do this manually too

  • /usr/share/applications/defaults.list holds the defaults (ie. system wide associations).
  • ~/.local/share/applications/mimeapps.list holds user specifics.

By the way: I assume you have software installed (ie. LibreOffice) that can open doc files?

From the comments and images added:

  • it could be that the file is corrupt. What a file is is based on the 1st byte of a file (and not the extension as Windows does). What you could do is set .txt files to open with Writer (just temporary) and see if it then does open and then save it under another name. Then reset opening txt to Gedit or what it was before.
  • Nope. Not that simple. - i.imgur.com/n7Fuy.png
    – jrg
    Aug 24, 2012 at 14:01
  • i.imgur.com/M9X1K.jpg
    – jrg
    Aug 24, 2012 at 14:06
  • hey, it takes time to take good lookin' screenshots! ;) only shows the rest of the libreoffice suite. - i.stack.imgur.com/CXMsd.png
    – jrg
    Aug 24, 2012 at 14:09
  • Changing default application which is set to open a file by default, does not changes the file MIME type. In my case I selected "Font viewer" as default application, but MIME type was same as before: ODF template (application/vnd.oasis.opendocument.formula-template) Feb 17, 2015 at 13:19
  • 1
    This doesn't answer the question. The question is about changing MIME type, not change the application that opens a mime type Jun 4, 2021 at 20:51

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.