JSI Tip 1516. Erroneous 1018 error during online backup of Exchange 5.5.

When you perform an online backup in Exchange 5.5 (information store or exchange folder), you may receive the subject error. The database is not actually damaged.

To correct the problem, use Regedt32 to navigate to:

HKEY_CURRENT_USERSoftwareMicrosoftNTBackupBackup Engine

In the right hand pane, double click the Max Buffer Size value name, and in the DWORD editor, set the buffer to 512 or less, using the Decimal Radix.