If you are using Office 2007 or 2010 with our Application Integrations installed and when you save a Word document to ND it is saving as a .doc instead of .docx, you may need to do the following.
1. Open Word and go to File>Options>Save
2. Make sure the "Save files in this format" option is set to .docx
If the above solution does not resolve this, you may need to make a change to the registry. NOTE: Before making any changes to the registry it is strongly recommended that you make a backup first.
1. Open the Registry Editor and navigate to "HKEY_CURRENT_USER\Software\Microsoft\Office\14.0\Word\Options" if you are using Office 2010 or "HKEY_CURRENT_USER\Software\Microsoft\Office\12.0\Word\Options" if you are using Office 2007.
2. You should see a "DefaultFormat" value. Make sure the data value is NOT set to doc. If it is, you can either change it to docx or remove it altogether.