How to Change Exchange Mailbox Message & Attachment Size Limit?

To manage user related issue in Exchange environment, both management and Powershell commands are available. Both options can help administrator to manage Permission, Organization, Protection, mail flow another section of Exchange 2016, 2013, 2010 and other below versions. Since as Emails messaging application, to manage the hundreds of user mailboxes is a challenging task and changing size limit of messages & attachments can be done by Powershell & Exchange Admin Center.

By default, when a new user mailbox is created in Exchange from Admin Panel, there is a fix size limit for sending and receiving the messages. When people need to send any message more than the default size limit, then the user faces file size issues. But, keep in mind that there are other settings available in Exchange that allows users to Determine & Change the maximum message or attachment size for sending and receiving the information.

How to Change Message Size Limits in Exchange 2010 / 2013?

To increase the message size limit of Exchange mailbox by using the PowerShell commands and GUI, you can change the default size limit from three places such as:

• Organization Transport Setting
• Send & Receive connector Settings
• Exchange User Mailbox Settings

Let’s have a look at the message size limit settings of Exchange 2010 in different places.

Increase Organizational Message Size Limits
As the default size of Exchange mailbox in Organization to send and receive messages is only 10 MB and increase this size limit of message and attachment according to your requirements by using either PowerShell command or Exchange Management Console.

PowerShell Command – Change Exchange 2010 Mailbox Message Limit

You can modify the Organizational message size limits by using cmdlet, But before that, you can view the previously set value of messages via Command:

• Run above command to view the default value of Transport Configuration and Connectors and Administrator Details.

• After running above Powershell command, we get the following information:

1. The maximum size of Transportconfig = 10 MB
2. Receiver connector = 35 MB
3. Send connector = 35 MB
4. Administrator Mailbox Size = Unlimited

After that, use command Set-TransportConfig cmdlet to change mailbox size.

- Set-TransportConfig -MaxReceiveSize 40MB -MaxSendSize 40MB

Set Exchange 2010 Mailbox Message Size limit via Exchange Management Console

Except for Powershell command, you can use the Exchange Admin Panel to set size, follow steps:

1. Open Exchange Panel as Administrator.
2. Go to the Organization Configuration option.
3. Hub Transport >> Global Settings tab
4. Go to Transport Settings >> Properties >> General tab

Here you find the “Transport Limit” section, set value of “Maximum receive size and Maximum send size” to “40960”.

1. Increase Receive Connector Message Limit

Receive connector on Exchange Server is only used to receive the messages. People can use multiple Receive connectors with the different size limit. The Exchange provides both PowerShell and EMC option to set the size limit of the message.

PowerShell Command to Set Exchange Mailbox Message Size Limit

To Change Receive Connector size limit using the PowerShell:

--ReceiveConnector “CONNECTOR NAME” -MaxMessageSize 40Mb

Exchange Management Console:
To increase the maximum mailbox message size limit for Receive Connector by using the Exchange console, perform these steps:

For Exchange 2010 Environment

1. At first, select the Server Configuration >> Hub Transport >> choose a Hub Transport server
2. Now, go to the Receive Connectors >> select a connector >> click on Properties >> General tab.

For Exchange 2013 Version

• Open Admin Panel and Click on Mail Flow
• Select the Desired Receive Connector and Go to “Maximum receive Message Size”

• And use the drop-down menu to change the message size limit:

Note: The valid range of message limit is from 1 t0 2047 (2GB).

2. Use Send Connector to Limit Exchange Mailbox Message Size Limit

Send Connectors in Exchange Server are used for sending outbound messages to the internet or any particular email addresses. Edge Transport servers also have a Send Connector for sending the inbound messages to the Hub Transport servers in an AD site. You can change the Send Connectors size limit for messages by using the PowerShell and EMC methods.

PowerShell Command:
To set the Send Connector size limit of the mailbox by using the PowerShell:

-Set-SendConnector “CONNECTOR NAME” -MaxMessageSize 40Mb

Exchange Management Console Steps to Increase Exchange Mailbox Message Size

To modify the maximum mailbox message size of Send Connectors, you need to perform these steps:

For Exchange 2010 Environment

• At first, select the Organization Configuration >> Hub Transport >> click on Send Connectors
• After that choose the connector and go to the Properties then click on the General tab

For Exchange 2013 Version

• Open EAC >> Mailbox flow section and Click on “Send connector”.

• To change Message size limit in Exchange 2013, select drop-down

Note: The valid range of messages limit is from 1 to 2096128 (MB)

After changing the messages size limit in Exchange 2010, 2013, users can send or receive large size message file, what happens, Exchange user wants to send a large attachment file along with messages for that need to change Exchange 2013 mailbox attachment size limit separately.

How to Set Attachments Size Limits in Exchange 2010 / 2013?

Email attachments can also affect the size limit of Exchange mailbox. So, you need to change attachments size limits. After increasing the attachment size limits, your mailbox database seems quite reasonable. But, this process still does not resolve the issue completely. However, the Exchange database grows anyway due to increasing of email traffic. Even a single small attachment can affect your Exchange mailbox size limit. So, it is necessary to set the Exchange mailbox limit. The only way to set the size of attachments is to use a hub transport rule. It can detect and block the messages if their included attachments are over a specified size threshold.

PowerShell Command to Change Attachments Size Limits in Exchange

In order to set up the hub transport rule, you need to follow the given below PowerShell command:

New-TransportRule -Name LargeAttach -AttachmentSizeOver 20MB 

-RejectMessageReasonText "Message attachment size over 20MB - email rejected."

Exchange Management Console – Exchange 2013 Environment

• In the EAC, go to the Recipients >> Mailboxes.
• Now, click on the mailbox from the list of user mailboxes that you need to change the attachments size limits and then click on Edit button.
• Next, from the mailbox properties page, click on the Mailbox Features

• After that, go to the Message Size Restrictions and click on View details option. It will show you the maximum size limit of attachments for sending messages and received messages and modify it.
• Finally, click on OK button and then click on the Save button to view your changes.

Conclusion

In this blog, we have discussed the process to change mailbox message & attachment size limit in Exchange 2010 / 2013 versions. As Exchange mailbox has a fixed size limit by default, which creates problem while sending & receiving the message & attachments of large size. Exchange offers 4 way to increase message file size limit such as transport config, send & receive connector and get mailbox rule using Powershell command and GUI (Exchange Admin Console) interface. Not only messages, you can control Attachment size of the mail files via Command. Follow the Powershell cmdlet or use Exchange Admin center to Exchange Mailbox message & attachment size limit.