This worked for me, thanks. Here's what I did:

• Installed Vista, SP1 and SP2 ang got stuck with Windows Update, even after four days of checking.
• Killed every Windows Update in progress (did NOT disable the service)
• Installed from MUC the updates listed (KB3205638, KB4012583, KB4015195, KB4015380 ) restarting the system after each update; for each one, killed Windows Update when the update was hanging too much.
• Windows Update went back alive from hell with more than 200 updates.

My PC is quite old and I have tried the microsoft fix it tool. The fix it tool never works. 

I have been trying to check for new updates from since yesterday (Tuesday 14th June) in the afternoon. It is now Wednesday morning (12 hours approx) and it is still checking. There is no error code, it is just checking for the updates.

Hi m#l:

If the initial "Checking for updates..." phase of Windows Update runs continuously without throwing an error message, this is a widespread problem that currently affects many Vista SP2 users.  Some users find that Windows Update will eventually run to completion if you let it run for several hours (or even days), but there is also a workaround posted on Dalai's webpage Search for Windows Updates takes forever? - A possible solution at http://wu.krelay.de/en/ that speeds up Windows Update for most affected users.  If you'd like to try Dalai's workaround, I'd suggest the following:

REVISED for the JUNE 2017 Patch Tuesday (valid as of 03-Jul-2017):

****IMPORTANT:  Extended support for Vista SP2 ended on 11-Apr-2017 and there will be no further security updates released for Vista SP2 and IE9 via Windows Update after this date. Please see the Microsoft support article Windows Vista Support Has Ended for more information.****

1. Disable automatic Windows Updates [Windows Update | Change settings | Important updates | Never check for updates (not recommended)] and re-boot to terminate any Windows Update sessions currently running in the background on your system.
2. As of 11-Apr-2017, the following four Win32K.sys / graphics component updates must be pre-installed on your system to speed up Windows Update: KB3205638 (rel. 13-Dec-2016); KB4012583 (rel. 14-Mar-2017); KB4015195 (rel. 11-Apr-2017); KB4015380 (rel. 11-Apr-2017).  If IE9 is installed then KB4014661 (the 11-Apr-2017 cumulative security update for IE9) should also be pre-installed.   If MS Office or the MS Office Compatibility Pack are installed, see Note 6 since Office-related products can also cause these "Checking for updates..." hangs.
3. Search your installed updates at Control Panel | Programs and Features | View Installed Updates to see if any of these speed up patches are already installed your system. When searching, enter the full KB number in the search box (e.g., "KB3205638" and not a partial string like "3205638").
4. Download the standalone update packages (.msu files) for any missing speed up patches from the Microsoft Update Catalog and save them to your Windows desktop - see Note 2 for download links.   Use the Vista x86 installer if you have a 32-bit OS; use the Vista x64 installer if you have a 64-bit OS.  See Note 3 if you have problems downloading the .msu installers.
5. Install any missing speed up patches in chronological order, from oldest (lowest KB) to newest (highest KB).  Double-click the .msu file on your desktop to start each installer - restart your computer when prompted after each update is installed.  See Notes 4 and 5 if you have problems running the .msu installers.
6. Once all missing speed up patches are pre-installed, run a manual Windows Update [Windows Update | Check for updates] to install your remaining updates.  See Note 6 if Windows Update continues to hang at "Checking for updates...".

**** IMPORTANT EDIT as of June 2017:  Microsoft released five special out-of-band security updates for Vista SP2 in June 2017 to patch vulnerabilities for the NSA-leaked exploits EnglishmanDentist, EsteemAudit and ExplodingCan

• see Tables 2 and 3 of the Microsoft Security Advisory 4025685: Guidance for Older Platforms: June 13, 2017.  These new security updates were posted on the Microsoft Update Catalog but will not be delivered via Windows Update.  Once Windows Update has successfully installed all available Vista SP2 and IE9 updates as of April 2017 (STEP

6 above) see the thread More Shadow Brokers Exploits Patched June 2017 for Win XP and Vista for instructions on how to install these June 2017 security updates.****

______________________

Note 1:  KB4015195 has replaced KB4012497 (rel. 14-Mar-2017).  KB4015380 has replaced KB3203859 (rel. 08-Nov-2016). The combination of KB4012583 and KB4015195 has replaced KB3191203 (rel. 11-Oct-2016).  KB4014661 has replaced KB4012204 (rel. 14-Mar-2017).

Note 2:  If you have a clean reinstall of Vista SP2 (i.e., no IE9 browser or MS Office) Dalai has posted a batch file on his website at http://wu.krelay.de/en/.  See the section titled Some Automation and click the link for **this script** that can be used to automatically install the required speed up patches KB3205638, KB4012583, KB4015195 and KB4015380.  

Other users can download 32-bit (x86) or 64-bit (x64) .msu installers for any missing speed up patches from the Microsoft Update Catalog by clicking the following links:

REQUIRED:

     KB3205638:  http://www.catalog.update.microsoft.com/Search.aspx?q=KB3205638 Vista

     KB4012583:  http://www.catalog.update.microsoft.com/Search.aspx?q=KB4012583 Vista

     KB4015195:  http://www.catalog.update.microsoft.com/Search.aspx?q=KB4015195 Vista

     KB4015380:  http://www.catalog.update.microsoft.com/Search.aspx?q=KB4015380 Vista

OPTIONAL (if IE9 is installed):

    KB4014661:  http://www.catalog.update.microsoft.com/Search.aspx?q=KB4014661 Internet Explorer 9 Vista

        

OPTIONAL (if MS Office 2007, MS Office 2010 or the MS Office Compatibility Pack SP3 is installed):

     See Volume Z's list of speed up patches for Office-related products on page 1 of peggybeggs' thread

     why has vista stopped automatic updates?

Note 3:  Some users have reported problems downloading the .msu installers from the Microsoft.com site with Internet Explorer 9 (e.g., the user never sees a pop-up to Run/Save the file).  If this happens use an alternate browser (I recommend Firefox ESR - Chrome is no longer supported for XP and Vista) or download the .msu installers to a USB thumb drive from another (non-Vista) computer and copy the .msu installers to your Vista desktop.

Note 4:  If you try to install a speed up patch that is already installed on your computer, download an installer that does not match the bit architecture of your OS (e.g., you try to run a 64-bit .msu installer on a 32-bit Vista machine), or try to install a speed up patch that has been superseded (replaced) by a newer update you will see a "not applicable" error - see the MS support article "The update is not applicable to your computer" error when you install Windows updates.

Note 5:  The standalone update packages (.msu files) will get stuck at "Checking for updates..." if there is a Windows Update session already running in the background on your computer.  Most users find that disabling automatic Windows Updates and re-booting is sufficient (STEP # 1), but if your .msu installer still gets stuck you can temporarily disconnect from the internet or stop your Windows Update service (wuauserv) as instructed in E-Chen's thread Vista Updates just keeps "Checking" before running these installers.  Unlike Windows Update, these standalone update packages (.msu files) are associated with the Windows Update Standalone Installer (C:\Windows\System32\wusa.exe) and can be installed on computers without an internet connection.

Note 6:  Please be patient when running Windows Update.  Depending on your system configuration, Windows Update can run for more than one hour before it finds all available updates if Vista SP2 is several months out-of-date, even after missing speed up patches are installed.

If you have MS Office 2007, MS Office 2010 or the MS Office Compatibility Pack SP3 installed there are additional speed up patches that must be installed to prevent Windows Updates from hanging during the initial "Checking for updates...." phase.  Volume Z maintains a list of these Office speed up patches on page 1 of peggybeggs' thread why has vista stopped automatic updates? .  After Vista SP2 reaches its end of extended support in April 2017 these Office products will continue to trigger "Checking for updates...." hangs on Patch Tuesdays (the second Tuesday of the month), and new speed up patches for these products will be added each month to Volume Z's post.

If you follow the instructions in this post and Windows Update continues to hang at "Checking for updates..." phase for several hours after all required speed up patches are installed then I would suggest you try using Torsten Wittrock's WSUS Offline Update tool.  This tool can be used to download and install important security updates for Vista SP2 (see the Legacy tab of the interface) and other Microsoft products like MS Office.  Be sure to download the special extended support release (ESR) v9.2.2 of this tool (released 03-Jul-2017) for older platforms like Win XP and Vista. The change log at http://download.wsusoffline.net/ notes that this ESR version of WSUS Offline Update will install the new June 2017 updates listed the Microsoft Security Advisory 4025685: Guidance for older platforms: June 13, 2017 for protection against the NSA-leaked exploits EnglishmanDentist, EsteemAudit, and ExplodingCan.

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32-bit Vista Home Premium SP2 * Firefox ESR v52.2.1 * NS Premium v22.9.4.8 * MBAM Premium v3.1.2

HP Pavilion dv6835ca, Intel Core2Duo T5550 @ 1.83 GHz, 3 GB RAM, NVIDIA GeForce 8400M GS

I wanted to say thank you b/c your method worked on Vista x64. You're a lifesaver

Hi AndrewL427:

Glad to hear you were able to get Windows Update working again, but all credit goes to German blogger Dalai for posting the original workaround on his website at http://wu.krelay.de/en.  Dalai has also provided background information at http://wu.krelay.de/en/info.htm on supersedence chains and why the manual installation of a small number of select IE9 and Vista SP2 graphics component and kernel-mode driver (Win32K.sys) updates will significantly speed up the"Checking for updates..." phase of Windows Update.

Just a reminder for everyone else that today (12-Sep-2017) is Patch Tuesday, the second Tuesday of the month.  If you followed the instructions on page 1 of this thread to ensure Windows Update has installed all available IE9 and Vista SP2 updates released before extended support ended in April 2017 and your "Checking for updates..." hangs return after April, be sure to read Volume Z's updated instructions on page 1 of peggybeggs' thread why has vista stopped automatic updates?.  Volume Z has already posted this month's list of new "speed up" patches that must be manually installed to speed up Windows Update if you have MS Office 2007, MS Office 2010 and/or the MS Office Compatibility Pack SP3 installed.

My Vista SP2 machine was fully patched as of April 2017 and it has an old version of MS Office 2003 Professional SP3 with the MS Office Compatibility Pack SP3 add-on installed.  After pre-installing this month's recommended KB4011064 (xlconv2007-kb4011064-fullfile-x86-glb.exe, released September 12, 2017) my "Checking for updates..." phase of Windows Update finished in about 4 minutes and found 3 additional MS Office security updates.

32-bit Vista Home Premium SP2 * Firefox ESR v52.3.0 * NS Premium v22.10.1.10 * MB v3.2.2

Just to say thank you to GWN - you are the Master.  I've been trying to sort this since last year; thanks to you I now have.