I am trying to fix an issue with my fathers laptop running 8.1 with all updates

I have set the default program for .doc and .docx to be open office

When he receives an email in the email app, it's correctly showing the OO icon

However, when you double click it, red text appears saying 'we cannot open this file, do you want to save?'

If you right click on the file, you get two options, one of which is Choose Program, but nothing happens - no file explorer is launched

Other file types do work. OO will open files saved to desktop. Have the nobbled it deliberately?