How to Update a DAT File

by Kayla Lowe

The DAT file is the data file used by McAfee antivirus software to store virus signatures so that the software can protect your computer. Usually, the DAT file is automatically updated through the automatic updates that the software installs periodically. Sometimes, however, those updates might fail, so in order to keep your computer protected, you must manually update the DAT file.


Create a temporary folder in the C: drive of your computer entitled “DAT.”


Navigate to the following website:, and download (the xxxx represents the latest DAT version).


Click on “Start,” “All Programs” and then “McAfee VirusScan Console.”


Click on “Access Protection,” and then deselect “Prevent McAfee Services from being stopped.” Click “OK” and exit the window.


Click “Start” and then “Run,” and input “services.msc” into the Run bar and press “Enter.”


Right-click “McAfee Shield” and “McAfee Framework” and click “Stop” before exiting the window.


Extract the DAT file you downloaded to your computer in step 2, and then copy the “avvclean.dat,” “avvnames.dat” and “avvscan.dat” files to the following location: C:\Program Files\Common Files\McAfee\Engine.


Click “Yes” when you are asked whether you wish to replace the existing files.


Restart the McAfee services by clicking on “Start,” “Run” and inputting “services.msc” into the Run bar and pressing “Enter.”


Right-click “McAfee Shield” and “McAfee Framework,” and click “Start.”


Prevent changes to McAfee services by clicking on “Start,” “All Programs,” “McAfee” and then” VirusScan Console.” Click “Access Protection” and then check “Prevent McAfee services from being stopped” and click “OK.”


  • check Hold down the control “Ctrl” key to make more than one selection at one time.
  • check You can check to see if the DAT file has been updated by opening the VirusScan Console and clicking on “Help” and then “About” to see the virus definitions, which should now reflect the new DAT version.


  • close Ensure that you restart McAfee services and prevent changes to them as well after you update the DAT file.

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About the Author

Kayla Lowe has been a freelance writer since 2008. She writes for various online publications and is also the author of the book "Maiden's Blush," a Christian-fiction romance novel. Lowe is pursuing a degree in elementary education.