%1 (%2) %3The log range read from the file “%4” at offset %5 for %6 bytes failed verification due to a range checksum mismatch. The expected checksum was %8 and the actual checksum was %9. The read operation will fail with error %7. If this condition persists then please restore the logfile from a previous backup.

This Warning event indicates that a checksum in a transaction log file failed verification. This error is similar to error -1018 in a database file, and indicates the log file has been damaged in the file system.

This issue can occur if the log file mentioned in the event has become corrupted. Exchange cannot repair damage to log files because of factors other than torn writes, which will be fixed automatically by the ESE. Hardware failures that randomly damage a log file cannot be overcome because the data cannot be reliably reconstructed. ESE event 477 indicates damage that cannot be repaired. The following are the most common error codes associated with this event:

• Error -501 = 0xfffffe0b = Jet_errLog fileCorrupt = Log file corrupt. An error -1022 is returned from corrupting the header of a log file. Corrupting other areas of the log file returns a 501 Jet_errLog fileCorrupt error. You may not be able to mount an Exchange store database due to the corrupted log file because the database has become inconsistent.

• Error -612 = 0xfffffd9c = Jet_errLogReadVerifyFailure = Checksum error in log file during backup. This indicates a corrupt transaction log file. A backup cannot be made of a corrupt log file and the backup will fail. A checksum Jet error indicates a hardware root cause and is caused by hardware, controller, or file system-level problems related to hardware. You may not be able to successfully perform an online backup of an Exchange store database.

• Error -573 = 0xfffffdc3 = Jet_errLogCorruptDuringHardRestore = Corruption was detected in a backup set during hard restore. You may not be able to successfully complete an online restore of an Exchange store database due to a corrupted transaction log in the restore set.

For information about ESE error codes other than the ones explained in this topic, see the following Microsoft Knowledge Base articles:

266361, Extensible Storage Engine 98 Error Codes 0 to -1048

266367, Extensible Storage Engine 98 Error Codes -1051 to -999999

This warning may indicate that the log file cannot be repaired.

To resolve this warning, do one or more of the following:

• Run diagnostic tests on your hardware.

• Repair or replace your damaged hardware.