HOWTO delete OS/2 and Posix Subsystems

First of all the subsystems are here so you can use OS/2 software written for OS/2 1.*. You also can use some Posix software but I never tried that one. If you want to disable the OS/2 and Posix Subsystem you can gain only 2MB memory saving. You may want that anyway.

WARNING: Using the Registry Editor incorrectly can cause serious, system-wide problems that may require you to reinstall Windows NT to correct them. I can not guarantee that any problems resulting from the use of the Registry Editor can be solved. Use this tool at your own risk.

  1. First go into the Registry editor with regedt32.exe, then get to the key HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Session Manager\Subsystems delete the Values
    "Os2:REG_EXPAND_SZ:%SystemRoot%\system32\os2ss.exe"
    and
    "Posix:REG_EXPANDSZ:%SystemRoot%\system32\psxss.exe".
    You can reverse this action by reentering the values.
  2. A more radical action would be to delete the files os2ss.exe and psxss.exe from %SystemRoot%\system32\. If you want to reverse that sometimes, make sure you save the files somewhere.