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Netmail Archive 5.x with Microsoft Exchange 2013


While migrating GroupWise XML files to Exchange 2013 mailboxes, large attachments fail to inject and the following error messages are generated:

Description: transaction error [add] the message exceeds the maximum supported size.


Description: transaction error [add] the request failed. the remote server returned an error: (507) insufficient storage


The errors are caused by a default setting in the EWS web.config file that restricts the size of messages/attachments that can be injected.

The (507) error messages are generated when the Maximum Allowed Content Length setting (IIS Request Filtering rules) is not set to support large files.

This article will explain how to modify the configuration to allow the injection of large files and prevent 'insufficient storage' errors from being issued.


CAS servers have their own attachment size limits that restrict the size of messages/attachments that can be injected into Exchange mailboxes.

By default, CAS servers only accept email that has a combined attachment size of less than 64 MB, and such attachment limits are likely to be exceeded during an injection job.

When the attachment limit is exceeded during injection, (507) insufficient storage errors will be generated.


Increasing the combined attachment limit is possible by modifying the Maximum Allowed Content Length value.

Since there two Exchange Server roles in Exchange 2013 deployments (CAS and Mailbox roles), this attribute must be modified for both server classes: CAS and Mailbox


To view the current value set on the CAS server, proceed as follows:

  • Open a command line on the CAS server (run as administrator)
  • Browse to C:\Windows\System32\Inetsrv
  • From the \Inetsrv directory, issue the following command:             appcmd list config "Default Web Site/ews" -section:requestFiltering

The default value is <requestLimits maxAllowedContentLength="67108864"> Note that a value of 104857600 represents 100 MBs in bytes.

The default value is usually sufficient, but very large attachments may also stored or sent, invoking (507) insufficient storage errors.

Depending on the size of the attachments or messages to be injected, the existing value may be increased to allow the injection of larger files as follows.


1) To modify the configuration to allow injection of large attachments, run the following script on each CAS server  (also from the \Inetsrv directory indicated above):

                                appcmd set config "Default Web Site/ews" -section:requestFiltering -requestLimits.maxAllowedContentLength:<content_Length_In_Bytes>


2) Next, while still in the same directory, run the following script to update the attachment limit on all mailbox servers:

                                appcmd set config "Exchange Back End/ews" -section:requestFiltering -requestLimits.maxAllowedContentLenght:<content_Length_In_Bytes>

3) Restart IIS to activate the configuration change by issuing the following command:   iisreset


Once the appropriate commands (depending on the server role) is run on all exchange servers, no further (507) errors should be observed upon injection of large attachments to Exchange 2013 mailboxes.


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