I was getting this error while trying to open a Word document using Word 2010. These steps also resolve the problem when opening an Excel document.

Problem/Error

Error: “Word experienced an error trying to open the file.”

Solution

This is corrected a couple different ways. You can either correct a specific file, or you can change your Word (or Excel, etc) trust settings to permanently remove this security feature.

For one specific file:

1. Go to the document properties in Windows Explorer (right-mouse click, select Properties).
   
   
2. Click Unblock.
3. Click OK.
4. You should now be able to open the Word document.

To permanently change the setting for all files:

1. Click File > Options
2. Click Trust Center >Trust Center Settings
3. Click Protected View
4. Uncheck the following boxes:
   1. Enable Protected View for Files originating from the Internet
   2. Enable Protected View for Files located in potentially unsafe locations
   3. Enable Protected View for Outlook attachments