Cannot open recently edited .docx files with Writer 4.2.8. on Ubuntu 14.04LTS (Engl)

I’m working on editing a 70-pages long text on which I made corrections the previous day. The file is a .docx written on Windows OfficeWord (I don’t know the version) and is in English. When I tried to open the file, the Writer kept either crashing or just doesn’t respond (and it worked fine yesterday!).
I know that if the file is bigger I should give it some time to open,but the only time it actually opened, the text was over 1000 pages long and it didn’t respond at all. I have already edited half of the text and now cannot access it!

I would reset my user profile. For details please refer to: