process name (process id) nameAn attempt to determine the minimum I/O block size for the volume “file name” containing “error code” failed with system error error message: “%8”. The operation will fail with error error code.

You receive the

following error in the Description of  Event ID 491: An attempt to

determine the minimum I/O block size for the volume [drive\path] failed

with [error #]. The operation will fail with error [error #].

This means that an

unexpected error was encountered while trying to use the volume specified in the

message. Specifically, an

error occurred when an attempt to determine the minimum input/output (I/O) block

size for the volume failed.

The cause depends on the Error listed at the end of the Description section

of the event.  The most frequent causes are listed below.

• Error -1032 =  0xfffffbf8 =  4294966264 = JET_errFileAccessDenied = Cannot

  access file – the file is locked or in use.  Another process has “stolen” the

  file. A virus checker may mistakenly quarantine a file, or a backup process

  may temporarily deny access.  A flat file backup system or anti-virus

  software may be running against the database or check file directories or the

  M: drive.  This error can also occur if the permissions on the folder that

  contain the files for the information stores are not sufficient for the stores

  to function properly.

• Error -1022 = 0xfffffc02 =

  4294966274 = JET_errDiskIO = Disk IO error.  The -1022 error is a generic

  error that appears whenever a disk input/output (I/O) problem prevents
  Exchange from gaining access to a requested page in the database or to a check

  file. A disk or controller failure may have occurred and access to the

  entire drive has been lost, sometimes temporarily. The actual physical drive

  may be no longer accessible or have an invalid file system, such as accidentally

  specifying the transaction log files path to the CD-ROM drive.  Check the

  System Log for I/O or drive errors near the time of the 491 Event. This issue

  may occur because the path for the check file (such as E00.chk) is not

  correct, which may be caused by a drive failure.

• For Error

  -1032, change the permissions on the folders that contain the information

  store files to the default

  permissions.  Configure the flat file backup and anti-virus software to not scan the Exchange server information store subdirectories or the M: drive. 

  Use Exchange-aware online backup and anti-virus software.

• For Error -1022, ensure that the drive for the information store

  files is accessible and that the path for the information store files is

  specified correctly.  If it is, run  “chkdsk /f /r” (without the

  quotation marks). If chkdsk does not resolve the issue, examine the

  permissions on the Exchsrvr folder structure. Make sure that SYSTEM has full

  control of Exchsrvr and all subfolders on each partition that contains

  Exchange data. If you still cannot mount the databases, troubleshoot any

  Windows NT file-level antivirus software running on the Exchange server. 

  Check the System Log for I/O or drive errors near the time of the 490

  Event. Check and correct the path for the check file (such as E00.chk).

• After correcting the root cause, if the database is inconsistent, restore

  from online backup. If there is no valid backup, you can restore the database

  to consistency using the “hard repair” (/p) functionality of the Eseutil

  utility, run isinteg -fix until all fixes are removed, and then mount the

  database and then ExMerge to a new, blank database. NOTE: Before doing this,

  you should always back up all information store files in a Storage Group

  (*.log files, *.edb files and *.stm files).