GW 2014 sp1, some users can not open attachments sent internally. Files show up as 0 bytes. If the attachment is sent from an outside address it goes thru without any problem, does not matter what type file it is, .xls .pdf .dwg. I had one of the senders open .xls file, do a save as and send the new file and that got through. Another sender tried to send an .xls file to same sender and that did not get thru. Support had me to a structural rebuild on the user, did not seem to help.