I have been testing a Powershell script to monitor the last install datetime of downloaded patches from WSUS on all my machines in the domain.

I found the path from http://technet.microsoft.com/en-us/magazine/gg153542.aspx

The paths which I use are: HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\WindowsUpdate\Auto Update\Results\Detect\

HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\WindowsUpdate\Auto Update\Results\Download\

HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\WindowsUpdate\Auto Update\Results\Install\

In all the paths above, there is a variable called LastSuccessTime which I use.

When I ran my script against all the machines, I cannot get anything from: Windows 2008 R2 64-bit Windows 2003 Enterprise 64-bit Windows XP 64-bit Windows Vista 64-bit

However, I was also get the registy info from Windows 7 64-bit or Windows 2003 32-bit.

The really weird things are:

1) I was able to use regedit to manually remote access those 64-bit machines and confirm that the path was valid and there is a LastSuccessTime field there. So, I can confirm that the same path applies to all OSes.

2) On those 64-bit machines, I was able to fetch other registry entries without any problem.

3) I reran the script and this time shortening the path to see where the access was aborted. It is in here


where the access was denied.

Could there be a restriction on reading the ...\WindowsUpdate registry folder while WSUS is active for 64-bit machines?


As it turns out, it has to do with the following:

1) The Powershell ISE was running on 32-bit machine and it was trying to remotely scan a 64-bit Windows OS.

2) WSUS running on a 64-bit Windows OS is a 64-bit app.

3) 32-bit Powershell ISE and 32-regedit cannot remotely "see" the following WSUS entries: HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\WindowsUpdate\Auto Update\Results

You can only "see" as far as:


The WindowsUpdate subkey is invisible to 32-bit app.

To solve the problem, always running Powershell on a 64-bit Windows OS and you can remotely "see" both 32-bit and 64-bit Windows OS.

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