(iBoyd)

Posts tagged: WMI

Windows PE 3.0 and the Missing WMI Class

By Boyd, October 12, 2009 9:46 am

Since I maintain the Windows XP Image for our lab machines, I was tasked with doing the same thing with Windows 7. When I rewrote our imaging tools last Spring, I created a WinPE 2.0 image that included the WMI package so that the imaging application could perform WMI queries in PE. I used WMI only to get basic information about the machine (Such as the Manufacturer, Model, Serial Number, and Disk Information).

While upgrading the WinPE image from 2.0 to 3.0 in anticipation of deploying Windows 7, I discovered that the Windows PE 3.0 base image (the same one that comes with the Windows AIK) was missing Win32_DiskPartition. I use this class to retrieve the number of partitions on the system disk so that I can make sure that each partitition (and its volume) has been assigned a drive letter so that I can search each drive for a preexisting configuration file. But why would Microsoft remove this class!? On a standard Windows 7 machine, the command “WMIC.EXE PARTITION” returned a list of partitions on the system, confirming that I wasn’t losing my mind. However, the command returned nothing when I tried it in Windows PE 3.0.

After lots of searching, I finally came across a post on Microsoft Technet where another developer ran into the same issue. Fortunately, he found a simple, but somewhat obscure, solution:

On a fully-installed Windows 7 machine, copy the contents of C:\Windows\System32\wbem
Mount the Windows PE 3.0 image and replace the contents of <mountdir>\Windows\System32\wbem with the wbem folder from the previous step

Using the Windows 7 wbem folder in your WinPE 3.0 image will make it several Megabytes larger, but at least you will be able to get to the missing WMI class(es) that you need!

Update 3/11/2010: After upgrading to the latest version of the Microsoft WAIK, I was unable to overwrite existing files in the WBEM folder (Access Denied). For some reason, the permissions are different on this folder now. Here is the workaround:

To take ownership of the existing WBEM folder and files, run this command: TAKEOWN /F <mountdir>\windows\system32\wbem /A /R
To grant administrators full control of the existing WBEM folder and files, run this command: ICACLS <mountdir>\windows\system32\wbem /grant Administrators:F /T

Once the permissions are updated, you will be able to overwrite files in the WBEM folder.

Update 3/18/2011: I was hoping that this issue would be resolved with the release of Windows 7 SPI and WinPE 3.1. Unfortunately, the problem still exists. However, I did some additional digging and found that, for me at least, there is only one file that I need to copy to the WinPE WIM fix Win32_DiskPartition: C:\Windows\Sysm32\wbem\en-US\cimwin32.dll.mui. Since the file doesn’t exist already in a fresh WinPE WIM, should shouldn’t have to deal with the ownership and permission issues mentioned above.

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