Symptom: Clicking the paperclip in Outlook doesn't do anything. Can't attach a file to an email message. (when using Google chrome browser)
Fix 1: Use internet explorer browser.
Fix 2: Use the Light version of OWA (Outlook Web App)
If you have webmail open, close the webmail browser. (Be sure to copy (CTRL+C) any email text you've written first) or save it in draft.
On the login screen click the Checkbox that says Use the light version of Outlook Web App
Login as normal - the screen will look slightly different but will all you to attach files and browse address book