Without seeing the file its going to be hard to help.  Excel is a terrible data medium.  One thing that jumps to mind is EU/US date differences for instance: MM/DD/YY and DD/MM/YY. Is it possible that you have values in that column which could be interpreted either way?  Because 12/27/2016 would not be decodable to DD/MM/YY, but others might.  This might be confusing the "guessing" proc import program.   Thats the only thing I can think off hand, however there could be any number of problems with an excel sheet - hidden things, hidden formats, differences in the data in each cell, just to name a few. Sounds like you have a real mess of a file. If you can get the problem data, just a few rows, in a datastep (see: https://communities.sas.com/t5/SAS-Communities-Library/How-to-create-a-data-step-version-of-your-data-AKA-generate/ta-p/258712) then could suggest a input() function to convert it, as: d_var=input(c_var,mmddyy10.); Should work. ... View more