Shell context menu option does not work when many items are selected

Question

I added an option to register a dll silently using the right click context menu by adding the following registry key:

[HKEY_CLASSES_ROOT\dllfile\shell\Register\command]
@="c:\\windows\\system32\\regsvr32.exe \"%1\" -s"

which I was using in XP. In XP when I selected many (200) dlls and right clicked them I would get the 'Register' option and could register them all in one go, silently. I have tried the same on my Win7 x64 machine and it works when I choose one or a few dll files, but as soon as I choose over 15 files, the register option does not appear in the context menu any more.

Why is this and how can I fix it?

Answer 1

Ahh seems I've been able to answer my own question:

the key is to add a new registry entry:

[HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer]
"MultipleInvokePromptMinimum"=dword:00000010

which disables the safety feature to remove options when a lot of items are selected, although it used to prompt me in XP which it does not do now, and which would be nice just in case...

the documentation on microsoft's web site says that setting it to 16 (as above) should let it treat as unlimited, but in my experience this did not work. Setting it to 16 allowed me to register up to 16 items at once. As soon as I selected more than 16 items it only registered the 1 item I right-clicked on. I found that by setting the registry to higher values I was able to run it on that many multiple items, so setting it to:

"MultipleInvokePromptMinimum"=dword:00000011

allowed my to register up to 17 items at once and setting it to

"MultipleInvokePromptMinimum"=dword:000001f4

allowed me to register up to 500 items at once.

hope this helps someone else and if anyone knows how to restore the prompt I'd be grateful