Topic Last Modified: 2006-07-07

The Microsoft® Exchange Server Analyzer Tool compares the value of a log file's Signature against the subsequent log file's Signature value to determine whether they match.

If the value of the log file's Signature value does not match the value of the subsequent log file's Signature, the Exchange Server Analyzer displays an error.

Exchange uses a series of log files, each exactly five megabytes, instead of writing all log information to a single large file. When a log file is full, Exchange closes it and renames it with a sequence number.

When a new sequence of transaction log files for an Exchange storage group is initialized, a Signature is written into the first log file, and copied into every subsequent log file. The Signature uniquely identifies a particular log file as a member of a particular log sequence.

There is never a case where log files that have different signatures should be found in the same folders. If this occurs, it indicates that foreign log files have been copied into the storage group or that the log files were reset without deleting all previous log files first.

The command Eseutil /ML LOGFILE can be used to display the Signature value for a log file.

For more information about Exchange Server transaction logging, see "Exchange Transaction Logging in Exchange Server 2003" in Using Recovery Storage Groups in Exchange Server 2003 (