What does Windows error code 1106 (ERROR_INVALID_BLOCK_LENGTH) mean?

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.

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.

What 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.

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.

Common misinterpretation

The error is not about a caller’s ordinary memory buffer length. It describes the physical/logical tape block format.

References

• Microsoft: System error codes 1000–1299