This file cannot be previewed because of an error with the Word previewer in Outlook

This file cannot be previewed because of an error with the Microsoft Word previewer in Outlook

Making mistakes while manipulating registry could affect your system adversely. So be careful while editing registry entries and create a System Restore point before proceeding.

1. Press Windows Key + R combination, type put regedit in Run dialog box and hit Enter to open the Registry Editor.


2. In the left pane of Registry Editor, navigate here:

HKEY_CURRENT_USER\Software\Policies\Microsoft\Office\15.0\Word\Options\Assist

3. As shown in the above window, right-click on Assist key and select Delete option. When this key is present, the issue occurs, hence we need to delete it.
You can now close the Registry Editor and reboot the system. After restarting the machine, you’ll find that Outlook can now preview Word files without any hitch.