1.	To determine the path and the file name of the .edb and .stm files for a database, use Exchange System Manager to view the Database tab of the properties dialog box for each database object.
2.	At a command prompt, move to the path of a database file.
3.	Run the following Eseutil command to view the header of the database file: eseutil /mh database_file
4.	Examine the Log Required field in the database file header. The Log Required field lists the range of numbered log files that are required to start this database. If the range is 0 - 0, no log files are required to start this database. This means that the database is in a Clean Shutdown or Consistent state. Note To examine the header of a database by using the Eseutil command, the database must be stopped. However, in all versions of Exchange Server, you may examine the header of the checkpoint file when databases are running. The procedure for examining the checkpoint file is the same for all versions of Exchange Server and is described in the “For Exchange Server 5.5” section. Viewing the checkpoint value lets you determine which log files can be removed without having to stop the databases. Log files may be removed that are older than the checkpoint log and that do not include the checkpoint log.
5.	If you are running a version of Exchange Server that is earlier than Exchange Server 2003 Service Pack 1 (SP1), you must convert the decimal range that is listed in the Log Required field to hexadecimal values. For example, if the Log Required value is 28217 – 28221, log files from 06E39 to 06E3D are required by this database. In Exchange Server 2003 SP1, the Log Required field has been enhanced to report both decimal and hexadecimal values. Note You can use the Scientific mode of the Windows Calculator to convert from decimal to hexadecimal. Start the Calculator, and then click Scientific on the View menu. Enter the decimal number, and then click Hex. Note In Exchange Server 5.5, log files are named Edbxxxxx.log, where "xxxxx" is a five-digit hexadecimal number. Because you can have up to four storage groups in Exchange 2000 Server and in Exchange Server 2003 with each storage group having a particular set of log files, the "Edb" prefix does not appear in the transaction log file names. In Exchange 2000 Server and in Exchange Server 2003, the "Edb" prefix is replaced with "E00," "E01," "E02," "E03." For a Recovery Storage Group, "Edb" prefix is replaced with "R00." The storage group log file name prefix appears in Exchange System Manager on the General tab of the properties dialog box for the particular storage group object. Therefore, if the storage group prefix is "E01" and if the Log Required entry is 28217 – 28221 (0x06E39 – 0x06E3D), the actual logs that are required are E0106E39.log to E0106E3D.log. You should examine the Log Required values for each database in a storage group before you remove any logs for that storage group.

You can safely remove all the numbered log files that are less than the lowest entry in any Log Required field for any database in the storage group. Remember to move, not delete, the log files.

Note The Log Required field may report a range of one log, but the corresponding numbered log file cannot be found. For example, The Log Required field may report a range of 28221-28221, but the log file that is numbered 28221 cannot be found. This can occur if the checkpoint is in the most recent log file. The most recent log file is always named with only the storage group prefix. For example, the most recent log file may be named E01.log. Until this log is full and until a new log is generated, the file name of the current log does not include the log sequence number.

You can verify the actual internal sequence number of the current log file by viewing the log file header by using the following Eseutil command: For example, if the log prefix is E01, use eseutil /ML E01.log. The lGeneration field of the log file header reflects the actual sequence number of the log file.

If you must restore an Exchange Server database from a backup, and if you want to recover the Exchange Server database without losing data, you must also restore all the transaction log files that were created after that backup was performed. If there is a break in the sequence of the transaction logs, you cannot roll forward past that break. In this situation, you must remove all the higher-numbered logs after the break. This includes the current log file.

Note Even if all the databases in a storage group are in a Clean Shutdown or Consistent state, you should not remove the most recent log file. If you remove the most recent log file, a new set of log files is generated, starting with the sequence number 0x000001. This new set of log files will prevent an Exchange Server database from a previous backup from being rolled forward.

For more information about how to repair an Exchange Server database, click the following article number to view the article in the Microsoft Knowledge Base: