Windows 11 Troubleshooting Guide: Error 1106 – Incorrect Block Size on Multivolume Tape Partition

Why This Error Happens

Error 1106 occurs when the Windows tape driver detects that the block size configured for the current tape operation does not match the block size recorded on the new volume of a multivolume partition. This typically happens because the tape drive or backup application switched tapes mid-job but failed to re-negotiate the block size parameter with the new media, often due to inconsistent formatting between tapes in the set. It can also result from outdated or corrupted tape drivers that mismanage block size persistence across volume boundaries, or from a backup job configuration that hardcodes a block size incompatible with how the tape was originally written.

Step-by-Step Resolution Guide

1. Verify the tape drive driver is current
   Open Device Manager (right-click Start → Device Manager), expand Tape drives, right-click your tape device, select Update driver → Search automatically for drivers. If a newer driver exists from the manufacturer (e.g., IBM, HPE, Quantum, Dell), download and install it manually from their support site instead of relying solely on Windows Update.

2. Check and reset the block size setting in your backup software
   Open your backup application (e.g., Windows Server Backup, Veeam, NTBackup-compatible tools, or vendor software) and navigate to the tape/media configuration settings. Ensure the block size parameter is set to variable or matches the value used when the original tape set was written (commonly 64 KB, but verify against your original job log).

3. Clear and rewrite the tape using a consistent format
   If the tape was written with mismatched block sizes across volumes, the set may be unrecoverable as-is. Use tapeinfo or the vendor’s diagnostic utility to inspect the tape’s current block size, then perform a fresh full backup using a single consistent block size across all volumes in the set.

4. Update tape drive firmware
   Check the tape drive manufacturer’s website for firmware updates. Outdated firmware is a common cause of block-size negotiation failures when switching tapes mid-partition. Apply the firmware update following the vendor’s specific installation utility (not through Windows Update).

5. Inspect Windows Event Viewer for correlating errors
   Open Event Viewer (eventvwr.msc) → Windows Logs → System, filter by Event ID 1106, and review the timestamp against your backup logs to confirm whether the error coincides with a tape swap event. This confirms whether the issue is media-specific or driver/hardware-specific.

Alternative or Verification Steps

• Run a test backup/restore job using a single, freshly formatted tape (not part of an existing multivolume set) to confirm the drive and driver handle block size correctly in isolation.
• If the error persists only with specific tapes, relabel and reformat those tapes entirely (full erase) rather than reusing them in a multivolume set, as residual block size metadata on the media itself may be corrupted beyond software-level correction.