I'm getting "Banned Contents alert" when I try and send an .xlsx file either from Outlook or from the Zimbra Web client. The error says
"banned contents (.wmf,docProps/Thumbnail.wmf)" but if I save the file as an .xls file, it goes right through.

I'm running Zim 6.04 on Cent5.4
Any ideas how to proceed would be helpful and appreciated!

Bounce back message:

BANNED CONTENTS ALERT

Our content checker found
banned name: .wmf,docProps/thumbnail.wmf