Microsoft Office 2010 introduced a new feature called as the Protected View feature. Trust Center contains security & privacy settings, which help keep your computer secure & safe.
Microsoft Office Trust Center
Files from the Internet and from other potentially unsafe locations can contain viruses, worms, or other kinds of malware, which can harm your computer.
To help protect your computer, files from these potentially unsafe locations are opened in Protected View.
By using Protected View, you can read a file and inspect its contents while reducing the risks that can occur.
When you see the Protected View Message Bar, decide how you want to proceed. This should depend on the color and the type of message you receive.
- If you know the file is from a reliable source, click Enable Editing.
- If you are unsure, Protected View lets you look over the file while turning off some functions like edit or print, that can trigger a virus to run. This allows you to read the file without potentially damaging your computer or network.
As mentioned, Trust Center contains security & privacy settings, which help keep your computer secure & safe. Go here to learn how to configure Trust Center. If you wish to disable Protected View, you can do so from the Trust Center.