Email Account Configured as (Exchange) in Windows 10 native email client, when replying to sender and attaching new files (I have tested xls, doc,word) it recipient don't get the attachment but the email is received but with out attachment, 

 

NOTE: this issue is only noticed in Windows 10 Native email client, otherwise if using Ms-Outlook2016 on both Windows or Mac Osx this problem is not present.