How to update a malwarebytes manual definition

Written by karie lapham fay
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How to update a malwarebytes manual definition
Updated antivirus and anti-malware defintion files help prevent invasions of your computer. ( Images)

No anti-malware program will protect your computer, unless it is up-to-date. Antivirus and anti-malware programs, such as Malwarebytes, rely on definition files, which are master lists of known malicious programs and viruses. Updating your definition files requires one of two methods: manual or automatic. Automatic updates occur when your anti-malware program downloads the new definitions on its own, according to schedule -- it does not require you to do anything. However, manual updates involve going to the definition location on the anti-malware's website, downloading the definitions and supplying them to your anti-malware program. Malwarebytes offers automatic updates to paid subscribers, but users of the free version must manually update their definitions. In addition, malware infections and corruptions can prevent automatic updates, in which case manual updates can get your computer up, running and protected.

Skill level:
Moderately Easy

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  1. 1

    Go to your Malwarebytes folder located on your computer:

    On Windows XP, click on the "My Computer" icon listed in your Start Menu. Choose "Local Disk (C)" to enter that directory. Select "Documents and Settings," then "All Users." Click "Application Data" and locate Malwarebytes. Enter the Malwarebytes' Anti-Malware folder to find the folder labelled "rules.ref." The direct path for this is "C:\Documents and Settings\All Users\Application Data\Malwarebytes\Malwarebytes' Anti-Malware\rules.ref."

    On Windows 7, follow the same procedure, entering your "C" drive, clicking on "Program Data" and then entering Malwarebytes. Select Malwarebytes' Anti-Malware and locate the "rules.ref" file. The direct path for this is "C:\ProgramData\ Malwarebytes\Malwarebytes' Anti-Malware\rules.ref."

  2. 2

    Right-click to highlight the "rules.ref" file, then select "Delete" on the drop-down box that appears. Alternatively, you can rename the file, right-clicking the file icon and selecting "Rename." Enter the new name in the space provided, then click in an area away from the name box to exit the edit name field. Renaming the old definitions prevents conflict with the new definition file, which bears the same name, while retaining the old definitions in case an error is made. Selecting a name such as "Old Definitions" with the date you renamed it is helpful.

  3. 3

    Visit the Malwarebytes definitions site, either by typing in the Web address into your browser or clicking on a link that takes you to the definitions site. The definitions may be found at ""

  4. 4

    Choose the option to either "Run" or "Save" the definitions file in the file download box that appears. Run will automatically install the definitions in the Malwarebytes folder from which you just deleted the old definitions. But if you save, you must either save to your desktop, then drag into your Malwarebytes folder, or navigate to the Malwarebytes definition file location by using the "Save In" options at the top of the download box. Find the Malwarebytes' Anti-Malware folder in which the old definitions resided and save to that location.

  5. 5

    Click on the icon representing the definition file, labelled MBam-rules.exe. Select "Run" in the pop-up box that appears.

  6. 6

    Indicate your language and click "Next" on the set-up page. Click "Install" to proceed, and "Finish" when the installation is complete.

Tips and warnings

  • Disable Malwarebytes so it will not run, removing it from the running processes inside your Task Manager, if you are unable to delete the old definition file. To do so, hit "Control, Alt and Delete" simultaneously, then choose the tab labelled "Processes" inside the Task Manager. Scroll down until you locate "MBam.exe," right-click to highlight, then select "End Process." Start Windows in Safe Mode, alternatively, to bypass restrictions that prevent you from deleting the definitions file.
  • You may also download the definitions file to a USB flash drive or similar storage device, then transfer to your computer if you do not have an Internet connection on the computer you wish to update.

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