(I'm not sure if this is a place to file bugs. Please let me know if it is not.) The KB2641653 update for Windows XP x86 checks this registry value and adds it when it's not present. HKLM, "SYSTEM\CurrentControlSet\Control\Session Manager\Memory Management", "SessionImageSize", 0x10001, 0x10 However, this entry is not brought to the installation CD when I use nLite to slipstream the update. This means the value will be missing in your new installed, nLited Windows. I have a workaround for this: