RDP and URL not valid messages while using Microsoft's Remote Desktop client

Last week it worked fine. This week, when I double-click the RD client Alias in order to connect to a remote Windows machine, I first received the message: "The RDP file is not valid. Notify your network administrator. [OK]". After clicking OK, a second message appears: "The URL is not valid. Notify your network administrator. [OK]". After clicking OK for that dialog, it then allowed me to connect to the remote box. What's going on? A Google search on both messages did not reveal anything that applied to the Mac, as far as I could tell. Any help would be appreciated.

Thanks,

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