Errors during virus and spyware definition updates or product upgrades

Microsoft Security Essentials uses Microsoft Updates (MU) service to deliver the virus and spyware definition updates and product upgrades. The definition updates and/or the product upgrade failures are generally caused by this service and results in a “0x8*******” error. If you encounter these errors, please write down the exact error code and follow these steps.

Step 1: Restart the Microsoft Update (MU) service

In Windows 7

  1. In Windows 7, click Start, and in the Search programs and files box, type services.msc, and then press Enter.

  2. Right-click Windows Update, and then click Start. If Start is unavailable, click Restart.

In Windows Vista

  1. In Windows Vista, click Start, and in the Start Search box, type services.msc, and then press Enter.

  2. Right-click Windows Update, and then click Start. If Start is unavailable, click Restart.

In Windows XP

  1. In Windows XP, click Start, click Run, type services.msc, and then press Enter.

  2. Right-click Automatic Updates and then click Start. If Start is unavailable, click Restart.

Step 2: Troubleshoot Microsoft Update (MU) errors

  1. Visit the following Microsoft website.

  2. On the "Windows Help and How-to" webpage, enter the error code that you received.

  3. Follow the steps and try again.

  4. To update the virus and spyware definitions, click the Update tab, and then click Update.

  5. To upgrade Microsoft Security Essentials, from the Help menu, click Upgrade Microsoft Security Essentials.

Step 3: Submit a case online if these issues continues to occur

  1. To get support for any issue you encounter with Microsoft Security Essentials, visit the Microsoft Security Essentials support website.

  2. In the list of issues, select the issue that is most relevant to the problem you've encountered.

  3. Next, select the type of support you'd like to receive: Community Forum or Email Support.

  4. If you think your PC is infected, select the option "I think my computer is infected" and then select Community Forum or Telephone Support.

  5. To connect to the Community Forum, click Forum, and then click Go to the Forums.

  6. To submit a support request by email, click Email, complete the email support form, and then click Submit.