Mac Error Code -56 — No Such Driver (nsDrvErr)

Overview

Mac error code -56 indicates a missing or incompatible driver, commonly seen when connecting external devices or storage media.

Key Details

• Error -56 (nsDrvErr) is a classic Mac OS driver error code
• Indicates the system cannot find a driver for the requested device
• Common with external drives formatted for other operating systems
• Can appear when mounting USB drives or network volumes
• Legacy error code still surfaced in some modern macOS operations

Common Causes

• External drive formatted with an unsupported filesystem (ext4, NTFS write)
• Missing driver for specialized USB or Thunderbolt device
• Corrupted disk driver partition on external drive
• USB hub or adapter incompatibility
• Third-party filesystem driver not loaded or corrupted

Steps

1. 1Check the drive format in Disk Utility — APFS, HFS+, and exFAT are natively supported
2. 2For NTFS write access, install a third-party driver like Paragon NTFS or Mounty
3. 3Try connecting the device directly without a USB hub
4. 4Try a different cable and port — USB-C ports are preferred on modern Macs
5. 5If the drive was used on Windows, safely eject it there before connecting to Mac

Tags

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Frequently Asked Questions