When I said "Have a bit over 16GB free RAM" that's from 32GB....
Oh and thanks for the useful comments.
> > Oh and yes, it does vary with extension.
> >
> > Plus I've also seen the shell stick around for longer before
> > disappearing. Although not having any CPU usage so could be Windows
> > getting around to zapping it after it's done.
> >
> > Here's a delay example (consecutive lines in ProcMon):
> >
> >
> "18:24:47.6325859","ZSHELL64.EXE","12892","RegCloseKey","HKCR\WOW6432Node\CLSID\{3C5E2B20-B911-44E2-A2DD-9F05E7B5E775}","SUCCESS",""
> >
> > "18:25:17.1963760","ZSHELL64.EXE","12892","Thread
> > Exit","","SUCCESS","Thread ID: 39868, User Time: 0.0000000,
> Kernel
> > Time: 0.0156250"
>
>
> So from your first reply, the delay is between ZSHELL64.EXE starting
> and the menu being displayed.
> As Matthias said and as I suspected, the delay is in ZSHELL64.EXE when
> it has to caculate what to display.
> Note: Windows Explorer has an advantage, because it stays loaded,
> whereas ZSHELL64.EXE only runs until the selection has been made.
>
> The easy part is
> HKCR\.ext => HKCR\progid\shell\*
>
> The slower part will be loading DLL's, for example
> HKCR\*\shellex\ContextMenuHandlers
>
> One odd thing from the ProcMon trace is the a 64bit process
> ZSHELL64.EXE is reading the 32bit view of the registry
> HKCR\WOW6432Node\..., which could mean it's trying and failing with a
> timeout to load a 32bit DLL into a 64bit process.
> i.e. the cause is somehing that has done an incorrect registration.
>
> That is assuming that it's not a ZSHELL64.EXE bug.
>
> Another posibily is some interaction with Antivirus.
>
> You stated how much memory the machine has, but not how much of it is
> free.
> i.e. could the issue by pageing memory back from the pagefile to
> memory.
>
> Ben