Hi Brian,
I know this isn't exactly the same as your use case, but I think it's similar enough to warrant looking into.
The Excel Automation Guide mentions macros that have a popup and how to deal with that.
https://portal.blueprism.com/documents/standard?title=excel&category=All
Here's the excerpt that I'm referring to:
In some situations, a running Macro requires a response from the user before it can complete. Such macros can cause Blue Prism to “hang” since the Run Macro action will not complete until it has received a response from Excel indicating the user has responded. If this is the case, you will need to use an action which creates a parallel thread while running the macro, meaning control is passed back to Blue Prism as soon as the macro is executed. Blue Prism can then be used to provide a response to the macro. You can request a copy of the Run Macro with Parallel Thread action from Blue Prism Support if you do not already have it in your environment.
So you may want to request the 'Run Macro with Parallel Thread' action and see if that'll help you toward a solution.
Hope it helps. =)
Dave
Dave Morris, 3Ci at Southern Company