Resolve SMB Network Path Not Found and Error 0x80070035

Before you begin

Applicable to supported Windows Server/client environments where the named role or feature is installed. Run read-only checks first from an elevated PowerShell or Command Prompt as appropriate. Replace example hostnames, domain names, addresses, ports and paths with values from the affected environment. Record the exact error, timestamp, OS build and scope of impact.

Production safety: obtain change approval and a verified backup before modifying AD DS, DNS, DHCP, firewall, IIS, storage or Hyper-V configuration. Ensure console/out-of-band access before network or remote-access changes.

Symptoms and likely root cause

Windows cannot open \\server\share and reports network path not found, system error 53 or 0x80070035.

DNS, TCP 445 path, Server service/share existence, routing, stale mappings or SMB dialect/security mismatch.

Diagnostic commands

Resolve-DnsName files01.corp.example.com
Test-NetConnection files01.corp.example.com -Port 445
Test-NetConnection 10.20.0.40 -Port 445
Get-Service LanmanServer
Get-SmbShare
Get-SmbServerConfiguration | Select EnableSMB1Protocol,EnableSMB2Protocol
Get-SmbConnection
Get-SmbMapping

Run the commands in order and save the complete output. The commands above are intended to establish the failing layer before a configuration change is attempted.

How to interpret the results

If IP works but FQDN fails, repair DNS. If TCP 445 fails by name and IP, inspect firewall/routing/service. Server service should run and exact share name must exist. SMB2/3 should be used; SMB1 is not a generic fix.

Practical correction

Check SMB-In firewall rules and upstream ACL. For NAS, verify supported dialect, signing/encryption and guest policy; update old firmware rather than enabling SMB1 across the fleet. Remove only the affected stale mapping/credential after saving open work.

Make one change at a time. Re-run the failed diagnostic after each change so the cause-and-effect relationship is clear.

Fallback and recovery

Restore prior firewall or SMB setting if it worsens access. Do not weaken SMB security globally. Test exact UNC path from a second client and authorised user.

Verification checklist

Success: TCP 445 is reachable, SMB negotiation succeeds and authorised user accesses the exact share path.

• Repeat the original failing operation from the affected client/user or service.
• Test from a second approved endpoint or subnet where relevant.
• Review the relevant event log/IIS log after the fix.
• Record the change, actual result and any remaining limitation.

Frequently asked question

Should SMB1 be enabled for an old NAS? Avoid it; update/replace the NAS or isolate a documented legacy dependency.

Official technical reference

Microsoft Learn — troubleshoot smb guidance

Use the official documentation for exact version support, prerequisites and any procedure that differs between Windows Server releases.

Technician field note

This runbook describes a controlled diagnostic path; it is not a universal guarantee that every environment has the same cause. If evidence does not match the expected result, stop and investigate rather than applying unrelated fixes. Do not mark the incident resolved until the original symptom is verified as cleared.