MaxMessageSize

Applies To: Windows Server 2003, Windows Server 2003 R2, Windows Server 2003 with SP1, Windows Server 2003 with SP2

HKLM\SOFTWARE\Microsoft\MSMQ\Parameters

Description

Specifies the maximum size of the message file. Because messages must fit in the file, the value of this entry also limits the size of messages that Message Queuing (also known as MSMQ) sends and receives.

When Message Queuing starts, it restores all persistent messages in message files. If it finds a message file larger than the value of this entry, then it might not operate correctly. Also, if it encounters messages larger than this value, then it blocks all further transports from the sending computer. To restore communication, you must set the value of this entry greater than or equal to the size of the message that exceeded this value, and then restart Message Queuing.

If you increase this value, you might be able to transmit larger messages between applications on the same computer. However, because this entry affects both incoming and outgoing messages, in order to send a larger message to other computers running Message Queuing, you must increase this value on all participating systems. If any system has a lower value, it might block transports from computers sending larger messages.

This entry does not exist in the registry by default. You can add it by using the registry editor Regedit.exe.

Activation Method

Message Queuing checks this entry only at startup. If you change the value of this entry, you must restart Message Queuing to make the change effective.

Note

• This entry affects Message Queuing only. It does not change characteristics of the network or network programs that might limit the size of messages.

Caution

• Do not change the value of this entry. Increasing this value might prevent you from sending messages larger than 4 MB. Decreasing this value might block transports between Message Queuing computers.