Is it safe to enable SMB1 for an old NAS?
No. Microsoft deprecated SMB1 in 2014 and removed it from Windows 11 by default because of serious security flaws exploited by ransomware like WannaCry. Don't re-enable it. The correct fix is to enable SMB2 or SMB3 on the NAS (all modern NAS units support them); replace the NAS only if it genuinely cannot.
Last verified July 22, 2026 · 2 official sources checked Updated
The honest answer is no — don't enable SMB1. It's tempting when an old NAS won't connect to Windows 11, but SMB1 is dangerous, and there's almost always a better fix.
Why SMB1 is unsafe
Microsoft deprecated SMB1 in 2014 and stopped installing it by default; Windows 11 ships without it. Microsoft states plainly: "We strongly recommend that you don't reinstall SMBv1. This older protocol has known security issues regarding ransomware and other malware." SMB1 flaws were the vector for the WannaCry ransomware outbreak. Re-enabling it re-opens that exposure for every device on your network.
The correct fix
- On the NAS, enable SMB2 or SMB3. Every current Synology, QNAP, UGREEN and TerraMaster supports them — in DSM it's Control Panel → File Services → SMB, set the maximum protocol to SMB3 and the minimum to SMB2.
- Update the NAS firmware; an old firmware may default to SMB1 until updated.
- Connect from Windows with a real account by hostname.
If the NAS truly can't do SMB2/3
A device that only speaks SMB1 is end-of-life and unsupported. Rather than weakening every PC that touches it, replace it — a modern two-bay NAS with CMR drives is inexpensive and secure. If you must bridge temporarily, isolate the old device on its own network segment, but treat that as a stopgap, not a fix.
Fix the connection, then protect the data
Once you can reach the NAS again, make sure the storage underneath it is sound — the right drives, healthy and backed up.
Related questions
- Why does my NAS say "network path was not found"?
- Why can't Windows 11 see my Synology NAS?
- Why is my NAS not showing up in File Explorer network?
- What drive should I buy to replace a failed drive in SHR?
- Should I replace all NAS drives at once or one at a time?
- Why does Windows say my NAS username or password is incorrect?
Sources
Every technical claim on this page is checked against manufacturer and standards documentation. Dates are when each source was last reviewed.
- Microsoft Learn — SMBv1 not installed by default (updated 2025-06-18) — checked 2026-07-22
- Microsoft Learn — Detect, enable and disable SMBv1/v2/v3 — checked 2026-07-22