Shell hooks in the absence of Explorer.exe

[Ron Russell]

I am in the process of developing a custom desktop for Windows NT. In my implementation of this custom desktop, there is a window along the bottom of the screen that emulates the behavior of the Windows NT Taskbar. This taskbar implementation sets a WH_SHELL hook and a WH_CALLWNDPROC hook to receive notifications concerning window creation, title changes, etc. During the early portions of development, this custom shell was always ran on top of Explorer.exe. Eventually the custom shell was moved to a test system whose policy file (ntconfig.pol) directs windows to run the custom shell at boot time rather than Explorer.exe. I have noticed that when this is the case, I no longer receive callbacks from the WH_SHELL hook procedure, although I still receive callbacks from the WH_CALLWNDPROC hook procedure. I can launch Explorer.exe from the custom shell and I begin to receive callbacks from the WH_SHELL hook. I can even end the Explorer.exe task from the taskmanager, and I still receive shell hooks. It seems that Explorer.exe must at least run once before I receive any callback from the WH_SHELL hook. I have discovered no information anywhere on MSDN that indicates that this is the case. Does anyone have any information as to why an application would not receive WH_SHELL hook procedure callbacks unless Explorer.exe has been started at least once on a system?

[Lost User]

When you do receive WH_SHELL callback, what process is the hook DLL in ?