I'm running into a problems I've never seen before. I'm working with Excel (.xlsx) and ArcEditor. I want to add my Excel tables into ArcMap to create XY data. In ArcCatalog, my .xlsx tables look as they usually do. They have the standard icons next to them. When I double click on the icon I see all of the names of all of the sheets inside the Excel file. If I drag one of these sheets into ArcMap, though, I get the following error: Connect Failed to connect to database. General function failure External table is not in the expected format. If I try to add the table to ArcMap using the AddData button, the tables look different. The icon next to the .xlsx table is for a Feature Dataset. (See attached) When I open the .xlsx file, none of my sheets show up. Instead, there is a single point file icon and next to it there is text that reads "No Geometry." (See attached) My .xls files are behaving normally. I can work around this problem by backsaving my .xlsx files, but I'd like to understand what's going on.