This issue may occur if an administrator has restricted the types of presentations that you can open in Microsoft Office PowerPoint 2010, in Microsoft Office PowerPoint 2007 or in Microsoft Office PowerPoint 2003. An administrator can set a registry key to restrict this functionality.

For PowerPoint 2010, the registry key can be set in the 2010 Office System Administrative Templates.

Important This section, method, or task contains steps that tell you how to modify the registry. However, serious problems might occur if you modify the registry incorrectly. Therefore, make sure that you follow these steps carefully. For added protection, back up the registry before you modify it. Then, you can restore the registry if a problem occurs. For more information about how to back up and restore the registry, click the following article number to view the article in the Microsoft Knowledge Base: 322756 How to back up and restore the registry in WindowsTo open files that are blocked by the registry, you can disable the restriction on opening presentations that were blocked by the registry settings of PowerPoint. To do this, click to expand the section according to which version of PowerPoint you are using.

1. Click the File tab.
2. Under Help, click Options.
   
3. Click Trust Center, and then click Trust Center Settings.
   
4. In the Trust Center, click File Block Settings.
5. To allow the opening of a file that is blocked, click to clear the check box for that file type.
   
6. Click OK two times.