How can I disable the "Do you want to allow this website to open a program on your computer?" warning for a specific program/moniker?

Solution 1:

This prompt can be disabled by the following registry edit:
HKCU: to affect current user only:

[HKEY_CURRENT_USER\Software\Microsoft\Internet Explorer\ProtocolExecute\YOUR_MONIKER]
"WarnOnOpen"=dword:00000000

HKLM: to affect local machine – for 32 bit machines

[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Internet Explorer\ProtocolExecute\YOUR_MONIKER]
"WarnOnOpen"=dword:00000000

HKLM: to affect entire machine – for 64-bit machines

 [HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\Microsoft\Internet Explorer\ProtocolExecute\YOUR_MONIKER]
"WarnOnOpen"=dword:00000000

Solution 2:

I've no experience of this, but the thing that springs to mind is using a software packaging tool that takes a 'before' and 'after' snapshot of your system?

i.e.

1. Disable as many services as you can that might be making changes to files in the background (automatic updates & AV software are typical examples that can interfere), or even better use a virtual PC with no software other than what is absolutely essential.
2. Take a 'before' snapshot of the filesystem and registry.
3. Execute the moniker for the first time, clear the checkbox and click 'Allow'.
4. Take an 'after' snapshot of the filesystem and registry.
5. Compare the two snapshots and look for changes that might be relevant.

If you can isolate the filesystem/registry change, you should be able to create a GPO (computer startup script or user logon script) that will apply the changes to the system/user. It might not be the cleanest solution, but it might just work.