XCON: 2026 and 3016 Warnings During Periods of High Server Use (257348)

IMPORTANT: This article contains information about modifying the registry. Before you modify the registry, make sure to back it up and make sure that you understand how to restore the registry if a problem occurs. For information about how to back up, restore, and edit the registry, click the following article number to view the article in the Microsoft Knowledge Base:

256986 Description of the Microsoft Windows Registry

SYMPTOMS

During periods of high server use, the following error messages may be logged in the application event log:

Source: MSExchangeMTA
2026 - An internal MTA error occurred. Contact Microsoft Product
Support Services. Unable to write to the message tracking log, error
1%.

Source: MSExchangeIMC
3016 - An error occurred while logging a message tracking record. This
will not affect message delivery. Verify that message tracking is
configured correctly.

Mail flow is not affected by these messages.

CAUSE

This problem can occur when the system attendant writes to the message tracking log (located in the Tracking.log folder under Exchsrvr). When the message transfer agent (MTA), Internet Mail Service, or other service sends these messages to the system attendant, the system attendant holds the messages in a buffer and only writes to the log if a number of messages that is specified in the registry (the LogFlushFreq registry value) is reached. The system attendant spends less time waiting for disk input/output to finish if you increase this buffer, which reduces or eliminates the 2026 and 3016 event IDs.

The default value of the LogFlushFreq registry value is 0x10 hexadecimal (16 decimal).

RESOLUTION

To resolve this problem, increase this buffer by changing the LogFlushFreq registry value:

WARNING: If you use Registry Editor incorrectly, you may cause serious problems that may require you to reinstall your operating system. Microsoft cannot guarantee that you can solve problems that result from using Registry Editor incorrectly. Use Registry Editor at your own risk.

Start Registry Editor (Regedt32.exe).
Locate the LogFlushFreq value under the following key in the registry:
HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\MsExchangeSA\Parameters
On the Edit menu, click DWORD, type 100, and then click OK.
Quit Registry Editor.

Stop and restart all of the Exchange Server services so that this change takes effect.