Hello, I have an Exchange 2007 server (all roles) and I have Windows & Mac clients. The problem I'm having is with message limits for the Mac users, which I understand utilizes Exchange EWS for it's limits. Users are unable to send attachments larger than aprox 20MB. This does not affect Windows clients. I used the settings in the following link to modify the attachment sizes: http://ministry-it.blogspot.com/2009/08/entourage-ews-attachment-limits.html Strangely, after applying these changes, I was able to send attachments as large as 15MB (I could not do this before making the changes) but 25MB attachments still are not sent. Please advise. Thanks