March 21, 2000

Most Microsoft Office 2000 applications maintain and display a history of most recently used files. Although this feature is convenient to users, it can post a security risk in some environments.

Under Microsoft Windows® 2000 only, you can install Office 2000 in a public access environment - an Internet café or airport kiosk – where anyone can use the applications. A business traveler might stop at the computer in an airport kiosk, connect to the company network or Web site, and open Office documents. The traveler can view, edit, and save personal files or confidential documents at the kiosk and then move on.

If the Windows registry settings that preserve the most recently used file history are enabled, the next user at the airport kiosk might be able to follow the trail to a list of the previous user’s confidential files.

Windows 2000 includes two Group Policy settings that disable the most recently used file history:

• Do not keep history of recently opened documents
• Remove Common Dialog MRU dropdown

Because Office 2000 manages common dialog boxes differently, however, Office does not recognize these Windows system policies. To disable the most recently used file history for Office applications, you must delete the appropriate subkeys in the Windows registry. This security workaround helps preserve customers’ security and privacy in a public access environment.

Delete the most recently used file list

Office exposes a history of recently used documents in the following locations:

• File menu
• Open and Save dialog boxes (File menu)
• Picture submenu (Insert menu)
• Insert Hyperlink dialog box (Insert menu)
• Microsoft PowerPoint start up screen

The following key in the Windows registry contains the settings that control the display of the most recently used files lists:

HKEY_CURRENT_USER\Software\Microsoft\Office\9.0\Common\Open Find

Within the Open File subkey, additional subkeys for each application contain several File Name MRU subkeys that control most recently used files history in Office applications. For example, the following subkey displays the file list in the Open dialog box in Microsoft Excel:

HKEY_CURRENT_USER\Software\Microsoft\Office\9.0\Common\Open Find\Microsoft Excel\Settings\Open\File Name MRU

You disable the most recently used file history by deleting the Open Find subkey from the registry.

To disable most recently used files lists

1. Create a registry (REG) file that deletes the following subkey:

   [-HKEY_CURRENT_USER\Software\Microsoft\Office\9.0\Common\Open Find]
   

   
   
2. Save the REG file in a convenient location. For example:

   Program Files\Microsoft Office\Office\MRU.reg.

3. For each Office application, create a batch file that starts the application and applies the REG file. For example:

   @start /wait winword.exe
   regedit /s "path\mru.reg"
   

   
   

   where path is the location where you store the REG file.

4. Store the BAT file in the same location as your REG file.

Redirect file extensions

After you delete the Open Find subkey, you must redirect file extensions to the batch file for each Office application. Note that after you redirect the shortcuts, all documents lose their application-specific icons and friendly descriptions.

To redirect shortcuts to the batch file

1. Start Windows Explorer.
2. On the Tools menu, click Folder Options, and then click the View tab.
3. Clear the Hide file extensions for known file types check box.

   This step displays file extensions in Windows Explorer.

4. Click the File Types tab.
5. In the list of file types, click the file type you want to redirect.

   Office application file extensions are listed at the end of this article.

6. Click Change, and then click Other.
7. In the Open With dialog box, locate the batch file you created for this application, select it, and then click Open.

Office application file extensions

The following tables list the file extensions associated with each Office 2000 application.