What is Protected View?

Office 2010 offers something new - Protected View. What is it? Protect view is another layer of security to protect the user from malacious documents. It is a sandbox designed to open documents from untrusted sources. There is a detailed article about it here: http://blogs.technet.com/b/office2010/archive/2009/08/13/protected-view-in-office-2010.aspx

To summarize it, you would see the Protected View for the following cases:

1. File opened/downloaded from Internet
2. Opened mail attachments.
3. Files opened from unsafe location.
4. File block policy: http://support.microsoft.com/kb/922850
5. File validation: 2010 performs additional verification on the file to
confirm that it is well defined. If it detects any anomaly it will open in
Protected View.

Of these five, 1,2 & 3 can be disabled:
1. Click File | PowerPoint Options | Trust Center tab
2. Click on Trust Center Settings... and select the Protected View tab.
3. Change the settings and close all dialogs.