Clearing the Windows NT Page File upon Exit

   Windows NT creates a virtual memory paging file to store infrequently accessed data, or memory overflow pages to give your system a larger space to work in than your physical memory (RAM, SDRAM, etc.).  In effect this page file helps NT to run several applications simultaneously, or very large applications on your machine.   No matter what you run with NT, you'll have an active page file.

    Why is it important to clear, or flush this file frequently?

    As you use your computer, NT is flushing data out to the page file periodically to run more efficiently and handle it's multi-tasking functions.   Unfortunately, this can include sensitive personal information, credit card numbers (if you use commerce online), or other unprotected data.  If not prevented the page file can store bits of information like this for minutes, hours, days, or even longer.   Even if you password protect your sensitive files, or encrypt them portions might be stored in your NT page file for exploitation by those that you don't wish to reveal the data to.  As a precaution it's best to turn on this undocumented feature to flush the page file when shutting down your system.  It'll overwrite the pagefile, and remove sensitive information from the possible snooping of others.

   How do I turn this feature on?

   It's pretty simple, but requires you to run REGEDIT.EXE (The NT system registry editor).  Follow these steps, and you can do this safely.  You might want to print out this page for reference.

   Step 1:

    Click on the [Start] button, and select [Run].  When the dialog box pops up and asks you the name of the program to run, enter the following     REGEDIT   and press enter.   This will run the registry editor.

    Step 2:

    In the Edit menu of the registry editor there is a menu item named [Find].  Click on this item and a dialog box will appear asking you what to look for.  Enter   ClearPage   in the space provided, and press the enter key.  (Note: Leave all of the radio boxes checked except the Match whole string only box.)

    Step 3:

    Be patient.  It will take NT a while to find the registry entry for you.  When it locates the entry it will be highlighted and contain the following name:

ClearPageFileAtShutdown

    Now double click on the entry.  Another box will appear and allow you to change the value for this entry.  The value should be  1  .  Depending on the version of NT you have (WorkStation or Server), there may be more copies of this entry in other locations.   Press [F3] to find more entries if they exist in the registry.  Usually this key will exist in about 3 locations.  Once you have changed all of the ClearPageFileAtShutdown entries to be the value  1  you can close the registry editor.  The next time you shut down NT, (an every other subsequent shutdown) your page file will be overwritten.   Simple huh?

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