(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: 1. After slipstreaming with nLite, extract the NLITE.IN_ in your i386 folder (of your installation files). 2. Open the extracted NLITE.INF, and add this line to somewhere in the [T] section HKLM, "SYSTEM\CurrentControlSet\Control\Session Manager\Memory Management", "SessionImageSize", 0x10001, 0x10 3. Save the file. 4. Compress the file with NLITE.INF cabarc or makecab, replacing the original NLITE.IN_ . cabarc -m LZX:21 N "I386\NLITE.IN_" "NLITE.INF" Update (May 2012): The new KB2676562 update replaces KB2641653, but the registry entry "SessionImageSize" is also present in KB2676562. This means the same bug will happen in slipstreaming KB2676562.