Windows Update service wuauserv hangs on starting, hogging all the spare CPU

I had this problem.  I simply installed Windows updates offline and the normal Windows Update service worked again.  Some update fixed it.

Download the latest version of WSUS Offline at http://download.wsusoffline.net/

Run the UpdateGenerator.exe until it's done

Run the UpdateInstaller.exe in the "client" folder and reboot.  Run and reboot several times.

Many recent updates should have installed.

Try normal Windows Update through Windows again.

You can try this: http://support.microsoft.com/kb/971058

and this: http://support.microsoft.com/kb/947821

You can try this: http://support.microsoft.com/kb/971058

and this: http://support.microsoft.com/kb/947821

So I tried both links but they didn't stop the 100% CPU problem.

This MS fixit https://support.microsoft.com/en-gb/kb/971058 found and corrected several things but left me with one error "Windows Update error 0x80070490"

Finally I found the solution here http://www.sevenforums.com/windows-updates-activation/341766-cannot-install-updates-error-0x8024001e.html

Basically, you rename C:\Windows\SoftwareDistribution and let windows recreate the files.

I had a similar problem.  After a delay, the windows update window would show a red warning and when clicked, a popup would say something like "Windows Update Service Not Running".  I tried various things found on the Internet, to no avail, including the Fixit tool for Windows update.  Finally I got it repaired by doing the following (found on another website):

When Windows Update Services goes bad there are any number of errors that may occur.  In the worst condition a corrupted WUS may well bring down your entire system.  Here are some troubleshooting tips for how to diagnose and solve corrupted WUS problems:

One of the most troubling potential issues is a lockup of WUS on boot.  Frequently this will bring up a notice that the Windows Update failed (as a "subcomponent" of SVCHOST.EXE).  When this happens it will present a dialog to send a message to Microsoft.  If you click to send the error message to Microsoft your machine then locks up and cannot be accessed without a reboot.

The following steps may assist you in fixing this issue:

1. DO NOT click the "send message to Microsoft" ok button.  Shut the machine down (Start/Shut down/Shut Down/OK).
2. When you bring your machine up repeatedly hit the F8 key on the keyboard.  If you get to the normal windows boot screen you didn't hit it soon enough.  If you get a menu offering you various boot modes, select "SAFE MODE"
3. You will still need to login - do so with a user account that has local administrator privileges on your workstation.
4. Once the machine is booted Choose Start/Run/Services.msc
5. Find the item that is marked "Automatic Updates". If it is marked as "started" right click on it and choose "Stop".
6. Close services.
7. Open My Computer
8. Go to Tools/Folder Options/View tab and be sure the following options are set accordingly:
   1. Display the contents of system folders is CHECKED
   2. Show Hidden Files and Folders is CHECKED
   3. Hide Extensions for known file types is UNCHECKED
   4. Hide Protected Operating System Files is UNCHECKED (You will receive a warning - proceed to unhide the OS files anyway)
9. Press OK on the Folder Options
10. Open C:\Windows
11. Locate and click ONCE on the "SoftwareDistribution" folder.  Right click SoftwareDistribution and choose RENAME.  New name should be SOLD (or anything else you'll remember).  Press Enter to save the new name.
12. Reboot the machine
13. Run Windows Update by going to http://update.microsoft.com .  You may need to reinstall some components.  Be sure it's not asking you to "upgrade" to Update.  If it is - go ahead and do upgrade to UPDATE first, then do a normal Windows update.

This problem is most often caused by an interrupted installation, or a corrupted installation patch download file.  Either will be fixed using this method.  If this does NOT work you would need to work on reregistering the Windows Update dll files, which I'll cover later.

Please answer all of the following diagnostic questions in a correspondingly-numbered list in your very next reply (no need to quote this post):

1. When (approx. date) did you purchase the computer?

2a. When (approx. date) did you install AVG Free (I assume) and was the computer fully-patched at Windows Update at the time?

2b. What anti-virus application was installed before you installed AVG, was your subscription still current, and did you uninstall it before you installed AVG?

3. Has a(nother) Norton application or a McAfee application EVER been installed on the computer?
4. Did a Norton free-trial or a McAfee free-trial [pick one] come preinstalled on the computer when you bought it? (Doesn't matter if you never used or Activated it.)

5a. Are ALL of the following updates listed in View installed updates (not Update History)? [1]

    • KB2621440, KB2641653, KB2665364 & KB2647518

    • KB2647516, KB2654428, KB2633874; KB2598479, KB2631813, KB2644615, KB2585542; KB2633171, KB2393802 & KB971029

    • KB2544521 or Windows Internet Explorer 9 [<=TELL ME WHICH ONE]

5b. When (exact date) was Windows Vista Service Pack 2 (KB948465) installed according to Update History (this time)? [2]

6. Is Firefox, Chrome or any other alternate browser installed?
7. Are you in the habit of using "Registry cleaners" (e.g., Registry Mechanic; System Mechanic; RegCure; RegClean Pro; Advanced SystemCare; McAfee QuickClean; AVG PC TuneUp; Norton Registry Cleaner; PCTools Optimiser; SpeedUpMyPC; Advanced System Optimizer; CCleaner)?
8. Have you ever done a Repair Install or a clean install of Vista for any reason?

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[1] Start | Control Panel | Programs and Features | View installed updates (in left-hand menu)

[2] Start | Control Panel | Windows Update | Update History (in left-hand menu)