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Windows Update error 80072efd 
Applies to all editions of Windows Vista.
Which edition of Windows Vista am I using?
If you receive Windows Update error 80072efd while checking for updates, the cause might be a high number of update requests on the Windows Update
servers. Close Windows Update, wait 10 to 15 minutes, and then run Windows Update again. You can also wait for Windows Automatic Update to run at its next scheduled time.
If you continue to receive this error, it might mean that a program running on your computer is preventing Windows Update Services (SVCHOST) from accessing the Internet. Programs that might do this include firewalls, anti-spyware software, web accelerators, Internet security or antivirus programs, and proxy servers.
To correct the problem, you might need to add the Windows Update website addresses to the blocking program's exceptions or "allow" list or allow Windows Update Service to connect to the Internet through port 80 and port 443.
To add the Windows Update websites to a firewall exceptions list
•Windows Firewall ships with this version of Windows and should already include these sites in the exceptions list. If you use a different firewall, refer to the software publisher's documentation to see how to add these websites to your firewall exceptions list:
•
http://*.update.microsoft.com
•
https://*.update.microsoft.com
•
http://download.windowsupdate.com
If the problem persists after you have added the Windows Update websites to your firewall's exceptions list, see this
Knowledge Base article on the Microsoft Help and Support website for additional solutions to try, or go to the
Windows Update Support Center website to request support by e‑mail.
Error codes this applies to:
•WindowsUpdate_80072efd
•0x80072efd