Windows Update Won't Run

• If the Windows Update facility refuses to run when downloading updates for the operating system or other Microsoft products, the anti-virus tool may be blocking it from running. Check the list of blocked services from within the anti-virus application and make sure Windows Update is marked as safe and trusted.
  
  

Software Updates Won't Install

• The anti-virus tool may be configured to allow updates to be downloaded, but then prevent them from being installed (viewing the necessary system changes as a security threat). Again, check the list of blocked services from within the anti-virus program and ensure that Microsoft's products and installation tools are not being blocked.
  
  

Other Issues

• Error messages and program crashes may be caused by a conflict between anti-virus software and updates run by Microsoft applications. Try disabling the anti-virus program temporarily while the update is being completed.