How to modify the free space in Windows PE

This applies to LANDESK Management Suite 9.0 and 9.5

In LANDESK Managment Suite 8.8, there was a button in the OSD tool that allowed you to manage the free space in the WinPE image.  

In LANDESK Management Suite 9 and 9.5, no such button exists. Because of the change to newer versions of Windows PE and the associated change to a .WIM file, this task must be accomplished another way.

The steps below are dependant on the OS running on the machine where you are editing the boot.wim, for simplicity's sake it is best to modify the boot.wim on a device with Windows 7, Server 2008 R2, or later, and then copy it back to the core if needed.

Important Note: Any increase in size of the free space inside the WinPE image requires that the corresponding space be available in RAM on the client machine. For example, a machine with only 512MB RAM WILL NOT load a WinPE image that is set to use 512MB of scratch space. The total space needed is approximately 365 MB plus free space. In WinPE Scratch Space can be set to 32, 64, 128, 256, or 512 MB.

Method for Windows 7\Server 2008 R2 or later:

1. Create the following folder structure C:\Mount\Bootwim
2. Copy \Program Files (x86)\LANDESK\ManagementSuite\landesk\vboot\boot.wim to the C:\Mount\ folder.
3. Open a CMD prompt as an Administrator.
4. Use DISM to mount the boot.wim:
   1. DISM /Mount-Wim /WimFile:C:\Mount\Boot.wim /index:1 /MountDir:C:\mount\bootwim
5. Use DISM to increase the Scratch Space (This example increases it by 256MB):
   1. DISM /image:C:\mount\bootwim /Set-ScratchSpace:256
6. Use DISM to commit the change, and unmount the image:
   1. DISM /Unmount-Wim /MountDir:C:\mount\bootwim\ /Commit
7. Copy the modified boot.wim from C:\Mount\boot.wim to \Program Files (x86)\LANDESK\ManagementSuite\landesk\vboot\boot.wim.
8. Update the PXE representatives. You can use the script from this article: Updating the WinPE image on PXE representatives

Method for Windows XP / Server 2003:

What you need:

A machine with Windows AIK installed

Access to \\<CORE>\ldmain\files\vboot\boot.wim

Note: This process involves modifying the boot.wim, or the WinPE image.

For more information about mounting and editing the boot.wim or WinPE image see How to manually modify the boot.wim WinPE image in LDMS 9

What to do:

To increase the free space, or scratch space as it is called, you need to mount the boot.wim image, open the registry and modify the following key:

HKLM\SYSTEM\ControlSet001\Services\FBWF\WinPECacheThreashold (REG_DWORD) and set it to the desired number. Acceptable values are 32 (default for WinPE <=4), 64, 128, 256 and 512. Then commit the changes to the WinPE image and update the PXE reps with the new image.

• Open a command prompt on the machine that has Windows A IK installed
• Create a new folder on the root of C: named mount (C:\mount)
• Navigate to the folder containing imagew. In my case it was in C:\Program Files\Windows AIK\Tools\x86.
• Run: imagex.exe /mountrw "<Path to boot.wim>\boot.wim" 1 c:\mount
• Run: regedit.exe
• Inside regedit, select the HKEY_LOCAL_MACHINE hive, then select "Load hive"
• Navigate to C:\mount\Windows\System32\config and select the file SYSTEM. See graphic below. (Note: DO NOT select the SYSTEM txt file or the SYSTEM.SAV file)

• Enter a name to reference the freshly loaded hive. For example, WinPE
• Navigate through the hive to \ControlSet001\Services\FBWF\WinPECacheThreshold
• Create a new REG_DWORD value named WinPECacheThreshold
• Set the new REG_DWORD to the value desired. Allowed values are 32 (default), 64, 128, 256, 512. (20, 40, 80, 100, 200 in hex)

• Once the value is set, select the key that you loaded the hive into, for example WinPE and then select File -> Unload hive. Close regedit
• Run the following at the command prompt to commit the changes to the WinPE image: imagex.exe /unmount /commit c:\mount
• Update the PXE representatives. You can use the script from this article: Updating the WinPE image on PXE representatives

Once this is done, you can reboot any clients back into WinPE and you should see the corresponding increase in free space.

Important Note: Any increase in size of the free space inside the WinPE image requires that the corresponding space be available in RAM on the client machine. For example, a machine with only 512MB RAM WILL NOT load a WinPE image that is set to use 512MB of scratch space. The total space needed is approximately 365 MB plus free space.