Excel Error Message
 

Hello,
What I "Save As" from a csv file to a Microsoft Excel file, I get an error
message with the new Excel file that says "excel found unreadable content..."
What can I do so this doesn't happen any more? It asks if I still want to
open the file and I click Yes and everything is fine, so there's no corrupt
info in the file, so I'm really confused as to what is causing this. Thanks
for any help!