Quick answer: Windows is refusing to talk to the share because the device behind it only supports SMB1, an old file-sharing protocol that Windows 11 and current Windows 10 editions no longer install. The proper fix is on the device: update the NAS, router or printer firmware, or set its minimum SMB version to SMB2 or higher. If that isn’t possible, turn on only the SMB 1.0/CIFS Client feature in Windows, copy what you need, and turn it off again.
In this guide
What the message means
The full text reads: You can’t connect to the file share because it’s not secure. This share requires the obsolete SMB1 protocol, which is unsafe and could expose your system to attack. Your system requires SMB2 or higher. Microsoft documents this as the message Windows shows when the other side of the connection only offers SMB version 1.
Nothing is wrong with your PC’s networking. Windows reached the device, the device said it only speaks SMB1, and Windows has no SMB1 client installed to answer it. Depending on the app, the same situation can also show up as The specified network name is no longer available, Unspecified error 0x80004005, System Error 64 or Error 58. If you get 0x80070035 (network path not found) instead, start with that guide, because it usually has a different cause.
Why it started happening now
SMB1 has been off by default for years. Microsoft’s support article states that Windows 11 has neither the SMB1 client nor the server after a clean install, and Windows 10 Pro dropped the client from version 1809. Enterprise and Education editions don’t include it either.
On Windows 10 Home and Pro machines that were upgraded, Windows ran a one-time cleanup: if the SMB1 client went unused for 15 days in total (time the PC was off doesn’t count), it uninstalled itself. That’s why a share that worked for years can suddenly fail after an upgrade or a new PC. Microsoft says the removal happens only once, so if you reinstall SMB1 it won’t be removed again automatically.
Fix 1: Update or reconfigure the device
Microsoft’s recommendation is to contact the maker of the SMB1-only product and get a software or firmware update that supports SMB 2.02 or later. In practice:
- NAS drives: install the latest firmware, then look in the file-service or SMB settings for a minimum or maximum protocol option and set the minimum to SMB2 (or SMB3 if offered).
- Routers with a USB drive: update the router firmware. Some older models never got SMB2 support for their storage feature.
- Printers and scanners that save to a shared folder: update the firmware, then check whether the scan-to-folder settings let you choose SMB2 or SMB3.
- Windows servers: on an old Windows file server, make sure SMB2 is enabled with
Set-SmbServerConfiguration -EnableSMB2Protocol $truein an admin PowerShell window. This command only works on a Windows server, not on a NAS.
If the device has no update and no SMB2 option, it’s worth planning to replace it. Microsoft’s own guidance warns against keeping SMB1 around because of its history with ransomware.
Fix 2: Raise the minimum protocol on a Samba or Linux share
Many NAS boxes and Linux servers use Samba. Since Samba 4.11 the default minimum is already SMB2, but older installs or edited configs may still allow only SMB1. If you can reach the configuration file (usually smb.conf), set this in the [global] section and restart the Samba service:
server min protocol = SMB2_02The setting name and the SMB2_02 value come from Samba’s 4.11 release notes. On a packaged NAS, prefer the vendor’s web settings over editing files, because firmware updates can overwrite manual changes.
Fix 3: Turn on the SMB1 client temporarily
Use this only when the device can’t be updated and you need to get files off it. Microsoft strongly recommends not reinstalling SMB1, so treat it as a short-term workaround. Install only the client part, not the server:
- Press Win + R, type
optionalfeaturesand press Enter. - Expand SMB 1.0/CIFS File Sharing Support.
- Tick only SMB 1.0/CIFS Client. Leave SMB 1.0/CIFS Server and the automatic removal entry as they are.
- Select OK and restart when asked.
PowerShell can do the same. Microsoft’s page shows Enable-WindowsOptionalFeature -Online -FeatureName SMB1Protocol, but that turns on the whole SMB1 feature. On recent Windows builds the client is its own sub-feature, which you can check and enable from an admin PowerShell window:
Get-WindowsOptionalFeature -Online -FeatureName SMB1Protocol*
Enable-WindowsOptionalFeature -Online -FeatureName SMB1Protocol-ClientRun the first line to confirm the exact feature names on your PC before enabling anything. If you’re mapping the share as a drive, our guide to mapped drive errors helps if the letter doesn’t reconnect afterwards.
Turn SMB1 off again
Once you’ve copied your files or moved the device to SMB2, untick SMB 1.0/CIFS File Sharing Support in the same Windows Features window, or run Disable-WindowsOptionalFeature -Online -FeatureName SMB1Protocol, and restart. Because the automatic 15-day removal only runs once, Windows won’t clean it up for you a second time.
Not the same as the Windows 11 24H2 NAS errors
Windows 11 version 24H2 brought separate changes: SMB signing is required by default, and guest access to shares is blocked on Pro. Microsoft’s file-sharing team lists errors such as The cryptographic signature is invalid and 0x80070035 for those cases. Those devices may support SMB2 or SMB3 just fine, so turning on SMB1 won’t help; the fix is to give the share a real user account and enable signing on the NAS. If shares or computers simply don’t appear in File Explorer, see network computers not showing, and for permission errors see Windows cannot access a shared folder.
Related guides
- Error 0x80070035 “The Network Path Was Not Found”: How to Fix It
- Windows cannot access a shared folder: how to fix it
- Network computers not showing in File Explorer: how to fix it
- The network connection does not exist: mapped drive fixes
- “Your organization’s security policies block unauthenticated guest access”: fix
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