In some occasions, a verification of a drive using a hex/disk editor (for example the Blancco Drive Eraser / Blancco 5 Hex Viewer), after a successful erasure, shows that there are unexpected patterns on the drive. There can be several reasons for that:
- Check the erasure standard that has been used to erase the drive. Some erasure standards include aperiodic random overwriting steps that write random data throughout the whole drive. Some drives can also write non-periodic data during a firmware-based erasure.
- You can check the used erasure standard from the erasure report.
- Check if the erasure process has written a Fingerprint onto the drive. The Fingerprint is a summary of the erasure report that is written in one of the sectors of the drive.
- To check if you had this feature on, you can load the image (used for the erasure) in Blancco Drive Eraser / Blancco 5 Configuration Tool and check if the setting in question is enabled or not.
- Check if the erasure process has written a Bootable Asset Report onto the drive. The Bootable Asset Report is a short asset report visible as a splash screen when the machine is rebooted.
- The Bootable Asset Report is written in the first 200 sectors of the drive.
- To check if you had this feature on, you can either boot the machine/drive without any CD/USB/PXE (the Bootable Asset Report should be displayed) or load the image (used for the erasure) in Blancco Drive Eraser / Blancco 5 Configuration Tool and check if the setting in question is enabled or not.
- In server environments, some RAID controllers write metadata onto the drive after the erasure has complete. This can also cause verification failures (more information in this article).
- Check if the erasure has (or has not) erased the remapped sectors and/or the hidden areas of the drive. If these sectors have not been erased, some tools may find some data there.
- Check the erasure report for more information.
- Check if the erasure has been a full erasure or a partial one. Partial erasures are possible in case the software is configured to automatically preserve Windows recovery partitions or in case the user has erased individual drive partitions only. Check the erasure report for more information, a partial erasure is accompanied with a disclaimer.
If you are still unsure about the erasure result, please contact the Technical Support team. Make sure that you include, at least, the erasure report in XML format and detailed information description of the case (issue report is also helpful/necessary in many cases).