Document ID: 267554
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The error message "Difference encountered in file data" (a000fe34 or e000fe34 or 00000000) is reported in a Backup Exec verify job operation
Details:
Final Error Code: a000fe34 HEX (0xa000fe34 HEX) or e000fe34 HEX (0xe000fe34 HEX) or 000000000 HEX
Final Error Description: "A checksum of the data has failed
Final Error Category:  Resource Errors
Error Text In Job Log:  "Difference encountered in file data"

If the Write checksums to media option is selected as a default backup option, checksums are calculated for each data stream written to tape or disk, and then written in a separate stream immediately following the data stream.

During a verify job operation, Backup Exec reads the data stream and  re-calculates the check sums and compares it with what is written in the media.
Backup Exec does not compare the files on the tape or backup to disk folder with the files on the hard disk. Instead, it performs a Cyclic Redundancy Check (CRC) verification of the data on the backup media. A CRC performs a mathematical calculation on a stream of data and returns a number that represents the content and organization of that data and uniquely identifies this data stream.  This CRC verification ensures the data was stored correctly and can be re-read.
This error could occur if Backup Exec incorrectly read the check sum or if the checksum could not be written to the media properly and was not able to verify the data.

 

This error occurs due to hardware/media related issues or because of other applications that run at the same time the backup does. The following list contains the most common reasons for this error and potential ways to resolve the problem:

1. Media related problems: { bad media}
a. Perform an "Erase" operation on the tape media
b. Use a new tape
c. When backing up to disk, use a dedicated disk partition that has been defragmented and run the Windows Error Checking Utility too, at a time when the backup is not running.  Make sure the drivers and firmware are also up to date on the controller (IDE, SCSI, or Fiber) that the hard disk(s) are attached to.

2. Tape drive related problems:
The following trouble shooting steps can be performed :
a. Clean the tape drive per the hardware manufacturer's recommendations.
b. Apply the latest drivers and firmware for the tape device.
c. Uninstall and re-install the VERITAS device drivers for the tape drive by following the steps below:
1. Launch Windows Explorer. Browse to the C:\Program Files\Symantec\Backup Exec folder. Locate the file TapeInst.exe and double-click on it. Select the bottom two choices to un-install/remove all VERITAS Drivers and delete entries for tape drives no longer available. Click Next, finish the wizard and when prompted to reboot, select No.
2. Stop and disable the Removable Storage Service (Control Panel | Administrative Tools | Services)
3. Reboot the server
4. Browse in Windows Explorer once again to the Program Files\Symantec\Backup Exec folder. Locate the file Tapeinst .exe and double-click on it. Select the top choice this time to use VERITAS Drivers, finish the wizard, and reboot if prompted.

3. Bad SCSI connection :
a. Use good quality cabling that follows the SCSI specification
b. For external cables, use heavy duty shielded cables. Under no circumstances should an external SCSI cable become detached from any connection while power is still applied to any device on the bus
c. For single ended internal cables, ensure that there is at least 1 foot of cable between devices. For single ended buses, be sure the overall cable length from termination to termination does not exceed the maximum bus length of 3 meters (roughly 9 to 10 feet)
d. Use active termination on both ends of the SCSI bus. All external devices should be set to supply termination power.
e. Make sure that no two SCSI devices are sharing the same SCSI ID
f.  Verify that there are no mirrored, duplexed, striped, or any other RAID configurations on the same SCSI bus that the tape drive is on
g. Do not use SCSI RAID controllers for tape devices

4. Third Party Applications that run at the same time the backup does:
***Windows Automatic Updates, active virus scans, and other backup applications (NT Backup, SQL Dump, etc...) should not run at the same time a Backup Exec Job is scheduled.  The other applications can affect Backup Exec's Ability to properly backup the data or to write the checksums to the media, so that a Verify Job can run after the backup.

If the above troubleshooting steps fail to resolve the issue, it is recommended to contact the hardware vendor and get the tape device(s) or hard disks that host the backup to disk files checked.



Supplemental Material:

System: Ref.#Description
UMI: V-79-57344-65076 Difference encountered in file data.
Error Code: 0xe000fe34 Difference encountered in file data.
Error Code: 0xa000fe34 Difference encountered in file data.

Products Applied:
 Backup Exec 10.0, 10.0 5484, 10.0 5520, 10d (10.1), 11d (11.0), 12.0, 12.5, 9.0, 9.1
Last Updated: November 18 2009 06:38 PM GMT
Expires on: 11-18-2010
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Subjects:
 Backup Exec
   Application: Verify
Windows Server 2003
   Information Development: Managing Devices, Troubleshooting

Languages:
 English (US)

Operating Systems:
Windows 2000

Advanced Server, Advanced Server SP1, Advanced Server SP2, Advanced Server SP3, Advanced Server SP4, Professional, Professional SP1, Professional SP2, Professional SP3, Professional SP4, Server, Server SP1, Server SP2, Server SP3, Server SP4

Windows NT

4.0 Server SP4, 4.0 Server SP5, 4.0 Server SP6, 4.0 Server SP6a

Windows Server 2003

Enterprise Server, Standard Server