— iIT-Services

Remove the document protection from Word files without knowing the actual password (doesn’t work for files with password protection to open):

1. Open the Word file in question (doc, docx)
2. Choose “File”, “Save File As”, and make sure the file format is set to “Rich-Text-Format (*.rtf)”. Close the file in Word (important!)
3. Open the new Rich-Text file with a text editor (e.g. Notepad or Notepad++). You can do so by dragging and dropping it into the editor window, or choose “File”, “Open File”, and set the file format to “All files (*.*)”.
4. Find (ctrl-f) “passwordhash” and replace the string that follows with something else (e.g. “nopassword”). Save and close the file in your text editor.
5. Re-open the modified Rich-Text file in Word, go to “Review”, “Restrict Editing” and click on “Stop Protection” (german version: “Überprüfen” – “Bearbeitung Einschränken” – “Schutz aufheben”). Uncheck all tick-boxes.
6. Done. You’ve unprotected your Word file without ever knowing the password.
7. Optional: Convert your file back to its original file format by selecting “File”, “Save As”, and choosing the original file format.

from: http://www.thinkoholic.com/2015/02/16/remove-unknown-password-protected-word-files.