Windows 7 Update Hangs and how to Fix

Problem:  Windows Update (Windows 7 Update) hangs.  Shows Downloading xx updates (0KB total, 0% complete).  Windows update hangs with 0% complete.

This article is obsolete.  Especially if Windows 10:
See this newer Keyliner Article:  Windows Update Hangs


Symptoms:

• Windows update hangs at the downloading step with no progress.
• Progress bar does not move
• Hangs, even if you wait a long time
• Likely, this is the first update that you have tried to run in a long time; perhaps an old image was restored.

Possible Solution:

1.  Confirm the machine is on the Internet.  Probably the easiest way to test is to launch Google and do a search on anything. Do not skip this check.  Confirm you can actually reach the net.

2.  Wait some period of time (~15 or 20 minutes), giving background processes time to download updates.  Be patient, even if no activity.

3.  Then click the Start Menu, Shutdown

If you see a "Shield" and "Install Updates then shutdown your computer", Windows needs to update the Windows Update program itself and I believe this does not show on the status bar.

4.  Gracefully shutdown and restart the computer.

When the machine begins to shut-down, you will see "Please do not power off or unplug your machine.  Installing update xx of yy.

5.  Re-open Windows Update and attempt again.

If there are no pending updates

Windows Update may appear to hang (showing 0% downloaded), but if you wait (again, 15 or 20 minutes), the update should begin, with percentage changes showing.  This is especially noticeable on large office Service Packs. Be patient.

Without pending updates, a simple reboot has helped in several instances.  I have noticed on some older-imaged machines, multiple reboots are required and after each reboot, Windows Update finds even more updates to apply.


If these steps fail:

Here are some technical items to use:

1.  Open and run the Microsoft Windows Update Troubleshooter

Link: 
http://windows.microsoft.com/en-US/windows7/Open-the-Windows-Update-troubleshooter


2.  Restart the Windows Update Services and clear the Update Cache.  This is safe to do at any time.  Follow these steps:

Start a command prompt (DOS prompt) as administrator (other-mouse-click the Command Prompt icon, select Run As Administrator).  Type these commands to reset the Windows update services:

net stop wuauserv
net stop bits
net start wuauserv
net start bits
exit
(then Reboot the computer and attempt the Windows Update again)

3. Consider running the System File Checker if you think your machine was compromised by a virus. 

Start a command prompt (DOS Prompt) as administrator.  Type this command to run the Windows System File Check (which can repair damaged system files):

sfc /scannow
(Type exit, then Reboot the computer when done)

4.  Consider re-installing the Windows Update Agent.  I have not needed this, but here is the Microsoft link.  This is safe to do.:

http://support2.microsoft.com/kb/946928/en-us



Comments:
I see this problem particularly when the workstation has been off the network for a long time or if Windows Update is set to manual and has not run in a long time. 

For example, with a laptop, I restored an image from 2 years ago, after pulling the machine out of moth-balls.  I found Windows Update hung multiple times and required 7 different reboots, as it applied 1.7G of patches and was finally caught-up.

I have seen other articles on the Net, suggesting flushing cache, registry hacks, disk-repairs and scan disks.  So far, that all has been nonsense.  A quiet reboot after waiting has worked for me on several different machines.