Hello there. Setting up Mac Mail to connect to an Exchange 2007 account requires both an Internal and an External Server Adress. But regardless of this a mail sent through Mac Mail cannot have attachments larger than 9.9 Mb !?! Does this have some relation to OWA - and is the same restriction vaild when using OWA ?

You have to change the attachment limit setting for EWS and OWA. Change to maximum sending sizes to OWA and EWS EWS C:\Program Files\Microsoft\Exchange Server\ClientAccess\exchweb\ews\web.config Change maxrequestlength to - <httpRuntime maxRequestLength="102400" /> OWA C:\Program Files\Microsoft\Exchange Server\ClientAccess\Owa\web.config Change maxrequestlength to - <httpRuntime maxRequestLength="51200" /> http://support.microsoft.com/kb/935848DJ Grijalva | MCITP: EMA 2007/2010 | www.persistentcerebro.com