How to Disable Protected View

You can easily switch from the Protected View to Edit mode with a click
but if you would like to permanently turn off that security setting such that all your future email attachments
/web documents open in regular mode, here’s the required setting.
 

Launch Microsoft Word, or any of the Office 2010 programs,
and go to File – > Options – > Trust Center – > Trust Center Settings.
 

Click “Protected View” here and deselect the option that
says “Enable Protected View for Outlook Attachments.”