The internet's favourite fix for an old device that will not connect is to switch SMB1 back on. It works. It also reopens the protocol a global ransomware outbreak travelled through. Here is the full picture, graded honestly.
This page exists because the honest answer is not the short one. Yes, Windows 11 disables SMB1. Yes, enabling it makes certain old devices connect. And yes, there is a documented, serious reason it is disabled — a reason with a name, a date, and hospitals in it. If your old NAS or scan-to-folder printer is the device in question, work through the safer routes first; they fix most cases. If SMB1 truly is the only road left, this page shows how to walk it as a last resort, narrowly — one client, one PC, knowingly.
SMB is the language Windows uses for shared folders, and like any language it has versions. SMB1 is the oldest dialect, from a different era of computing. Modern Windows, NAS boxes and printers speak SMB2 and SMB3. But some genuinely old devices — a decade-old NAS, an elderly multifunction printer that scans to a folder, an ancient media player — speak only SMB1. When one of those meets Windows 11, the connection simply fails, and the trail of forum posts leads to one seductive instruction: turn SMB1 back on.
Before following it, understand why it is off — because it is not off by accident or laziness on Microsoft's part.
SMB1 was designed before security was a serious feature of the protocol: no encryption, weak signing, and a long list of implementation flaws found over thirty years. It became infamous in 2017 when the WannaCry ransomware outbreak spread from machine to machine through an SMB1 vulnerability, hitting hospitals, railways and factories worldwide in a day. Microsoft had already been deprecating SMB1 by then; since Windows 10's later versions and throughout Windows 11 it is not installed by default, and Windows may even remove it automatically if installed but unused.
That history is why this page grades the advice honestly: enabling SMB1 is not a harmless toggle. It re-opens a protocol that attackers actively scan for, on the PC doing the enabling.
Many failed connections get blamed on SMB1 that are actually the ordinary gates — profile, credentials, permissions. The SMB1 diagnosis is narrow: the device is old, everything newer connects to the same shares fine, and this device cannot even negotiate. Check the state of the feature on Windows with PowerShell: Get-WindowsOptionalFeature -Online -FeatureName SMB1Protocol — on a healthy modern PC it reports Disabled.
Also check the device's own settings first. A surprising number of 'SMB1-only' NAS boxes and printers have a firmware setting for SMB2 minimum that was simply never switched on, or a firmware update that adds it. Ten minutes in the device's admin page can retire this entire dilemma — check before you downgrade your PC.
One — update or reconfigure the device to SMB2/SMB3, as above. Permanent, free, and fixes the cause. Two — change the workflow, not the protocol: let the old printer scan to email or a USB stick instead of a folder; pull files from the old NAS once, migrate them to a modern share, and retire it. Three — isolate the risk: if the device must live on, put the SMB1 conversation on one sacrificial machine or a dedicated old PC that holds nothing valuable and browses nothing — not on your main machine with your documents and browser.
Four — the last resort, knowingly: enable only the SMB1 Client (not the Server) on the one PC that must reach the device, via Windows Features → SMB 1.0/CIFS File Sharing Support → SMB 1.0/CIFS Client. Connect, do the job — and turn it back off when the device is retired. Treat it like leaving a ladder against the house: acceptable for an afternoon's work, not as furniture.
You will find guides that enable SMB1 across every PC 'to fix sharing' wholesale, and guides that enable the SMB1 server so old devices can connect into a Windows 11 PC. Both turn a one-device compatibility problem into a network-wide weakness. If a technician or tutorial proposes that as a first step rather than a documented last resort, that is the measure of the advice. The complete picture — what the video demonstrates for your exact device — is worth more than any blanket instruction.
Every check in this guide, shown live on a real Windows 11 PC — the complete network folder fix, step by step.
▶️ Watch Full VideoThe risk is smaller on a private home network than in an office, but it is not zero: the danger arrives with any infected device or malicious download that can reach the PC with SMB1 enabled. That is why the graded advice is client-only, one PC, and off again when the old device retires.
Very possibly — Windows 10 often still carried the feature from an upgrade, while a clean Windows 11 does not install it. But confirm the scanner's own SMB setting and firmware first; many models gained SMB2 support in a firmware update that was never applied.
No — that is designed behaviour. If Windows detects the SMB1 feature installed but unused for a period, it may remove it automatically. It is another sign Microsoft treats the protocol as retired. If you re-enable it as a last resort, expect Windows to keep tidying it away.