sorry no registry error and it sure isn't a Corel file. The files have been securely uploaded that way into our database for months prior to me working on this project and all (including the current ones I need to work on) end in _cdt (not .cdt) and come from an insurance carrier.
I saw one file there from an earlier month that ended in _cdt.xlsx so apparently someone before me was able to convert. I thought hmm, maybe I can change the file name and add that extension, but it refuses to open. I have no problem opening the file as is without the extension into notepad or even Excel, but like I said, it looks all run together. First two rows are a different length (shorter) with extra spaces. All the rest are really huge.