| Previous | Next |
| ERROR_PARTITION_FAILURE | ERROR_DEVICE_NOT_PARTITIONED |
ERROR_INVALID_BLOCK_LENGTH
when accessing a new tape of a multivolume partition, the current block size is incorrect.
ERROR_INVALID_BLOCK_LENGTH means that the block size configured for the tape drive does not match the size required by the newly loaded volume or backup set. In this case, the decisive context is multi-volume tape backups and restores, together with configured and expected block sizes, variable/fixed mode, and drive capabilities.
Where the result appears
- multi-volume tape backups and restores.
- fixed-block tape formats.
- media changes within a spanning archive.
- drive configuration carried over from a previous cartridge.
Typical causes
- the next volume was written with a different block size.
- the application failed to restore the cataloged block mode after media change.
- the wrong cartridge or backup family was loaded.
- drive, firmware, or format translation changed the effective block length.
Evidence to collect
- configured and expected block sizes, variable/fixed mode, and drive capabilities.
- volume sequence, media identity, and backup format metadata.
- the final settings on the previous tape and first records on the new tape.
- sense data and any automatic block-size detection result.
For this condition, begin the investigation with configured and expected block sizes, variable/fixed mode, and drive capabilities. Correlate it with volume sequence, media identity, and backup format metadata and check whether the next volume was written with a different block size. Capture the original this result immediately after the failing call so later cleanup does not replace the thread-local error value.
Handling and recovery
Set the drive to the block mode recorded for that volume before resuming. Verify the cartridge sequence and format first; guessing block sizes can produce misleading reads. Keep block-size metadata with each volume rather than only with the overall job.
Any retry policy for this Win32 error should be tied to evidence that the application failed to restore the cataloged block mode after media change has changed. Before another attempt, verify the final settings on the previous tape and first records on the new tape. If drive, firmware, or format translation changed the effective block length still applies, stop the retry sequence and preserve the first diagnostic event.
Common misinterpretation
The error is not about a caller’s ordinary memory buffer length. It describes the physical/logical tape block format.
Guidance for developers
When surfacing this result through another layer, retain its Win32 domain, numeric value, and the operation described by fixed-block tape formats. A useful telemetry record also includes sense data and any automatic block-size detection result. For the-related handling, decisions must use the numeric value and documented API contract rather than localized wording.
A focused test should reproduce the condition in which the wrong cartridge or backup family was loaded, assert this result, and confirm that the program releases resources associated with media changes within a spanning archive. The recovery test should also verify that configured and expected block sizes, variable/fixed mode, and drive capabilities is refreshed before the operation resumes.
References
Looking for a different code? Search another status or error code.