Just a FYI, since we ran into this when testing (right before an upgrade and deployment, no less).

Sage Exchange Desktop 2.0 is NOT compatible with Sage 500, despite the advertising of availability or lack of documentation regarding compatibility.

From SPS Support:

Sage Exchange Desktop 2.0 is not a replacement our existing Sage Exchange Desktop application. Please do not install Sage Exchange Desktop 2.0 on any workstation. It will not function with your existing Sage solution.