Shapefile export issue - Arcmap is producing CAD files instead of Shapefiles

Dear ArcGIS community -

Perhaps someone can offer some advice for this issue:

I recently installed AutoCAD on this computer, and somehow,
ArcMap is no longer exporting true shapefiles (.shp) but instead "AutoCAD Shape Source" files.
These load and process just fine in ArcMap itself, but the Autocad format is not compatible
with the upload needs of the ArcGIS.com web mapping application.

Is there some setting that I can change in ArcMap that will make it go back to normal (.shp) export format?

Thanks.