MAIL SERVERS

Microsoft Outlook 2010 blocks attachments that exceed 20 megabytes (20480 KB). If your attachments exceed this limit, the error message “The attachment size exceeds the allowable limit” appears.

This limit prevents your computer from continually trying to upload very large attachments that exceed the limits of most Internet service providers (ISPs) (ISP: A business that provides access to the Internet for such things as electronic mail, chat rooms, or use of the World Wide Web. Some ISPs are multinational, offering access in many locations, while others are limited to a specific region.). This limit applies whether you are adding one large attachment that is greater than 20 megabytes (MB) or several attachments whose sum total size is greater than 20 MB.

If you are using an Exchange Server account, the limit is controlled by your Exchange Server administrator. If your Exchange Server is configured to use the default limit, you receive this error message if the sum total of the attachments is greater than 10 MB (10240 KB). Only your Exchange Server administrator can change this limit.