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+1. Until there is native support, I just wanted to add that you can use the legacy driver ("Microsoft Excel Legacy (*.xlsx)") on the file format option and that will read .xlsb files successfully. It still involves several extra clicks, and I haven't yet figured out how to write to xlsb; so native support would be great. If you don't have the legacy driver, this post *may* help. I put a sample workflow in the public gallery: https://gallery.alteryx.com/#!app/XLSB-example/57582003a248970bdc39e572.
Thank you very much for inow including the XLSM format input for Alteryx, that is something that I needed for a while, but as I have other clients you us the XLSB, excel binary format, I need to find a way to input that into Alteryx and right back into it.
Please consider making this on a possibility on your next release.