not all installations use the assemblies that reference Outlook.

I have an app which reads schedule information from a variety of sources, one of which may be Outlook.

On systems where the user wants to access Outlook calendars, obviously they need the Outlook .DLL 11.0.0.0 in the GAC. But if a user isn't going to access Outlook at all and/or doesn't have Outlook installed on his/her PC, I don't want to prohibit them from installing and running the app.

So is there a way to allow an app which references the Outlook .dll in one of it's assemblies to run, without having the Outlook .dll in the GAC? I don't mind having an error generated if the user tries to access Outlook if they don't have it on their machine, but I do need my app to run on all machines whether Outlook is installed or not.

Any way I can accomplish this?

thanks. Using .Net 3.5SP1 and WPF