"The attachment could not be opened"

Introduction

The "The attachment could not be opened" error is a known issue that occurs when large email attachments cannot be opened through Exchange Web Services (EWS), resulting in a storage-related error. This page explains the cause of the issue and describes how to resolve it by adjusting the EWS configuration on the Client Access servers (CAS).

Problem

The following errors may occur when attempting to open an attachment:

• The attachment could not be opened.
• The remote server returned an error: (507) insufficient storage.

Cause

This issue is usually caused by the size of the attachment. EWS limits access to large attachments by default, but this limit can be extended.

Solution

To resolve the issue, edit the EWS configuration file on all CAS servers.

To change the maximum message size for Exchange Web Services clients, update the value of maxAllowedContentLength and all instances of maxReceivedMessageSize="67108864" in the following file:

%ExchangeInstallPath%ClientAccessexchwebewsweb.config

info

Note: Updating to Exchange 2013 SP1 should also resolve this problem.