How to disable SMB 1 or NetBIOS in macOS — by Apple Support

advancedpageLink only (©)

Apple's admin article on /etc/nsmb.conf, a file that does not exist by default: under a [default] section, protocol_vers_map=6 stops SMB 1 and port445=no_netbios stops NetBIOS fallback for outgoing connections. Deleting the file reverts it. Apple says these are on for compatibility with third-party products, so turning them off may affect older devices; editing /etc needs sudo.

Quick steps

Create /etc/nsmb.conf with a [default] line (sudo tee -a)
Add protocol_vers_map=6
Add port445=no_netbios
Delete /etc/nsmb.conf to revert

Paraphrased from the source. Menus can differ by version, so check the original for full details.

Read the full article on support.apple.com

Source: How to disable SMB 1 or NetBIOS in macOS by Apple Support. Licence: Link only (©).

Source reviewed: 2026-11-02
Link checked: 2026-11-02
Tested hands-on: Not by Oddbyte.Me

smbnsmb.confnetworkingmacos

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