# Networking: Windows error 64: The specified network name is no longer available — SMB session dropped

**Code:** `The specified network name is no longer available (64)` · **Category:** Networking · **Seen on:** Windows, Networking

A connection to a Windows file share was cut while in use.

## Meaning

The SMB session broke, from a network drop, a server restart, a firewall or antivirus resetting the connection, or an SMB signing/version mismatch. Check connectivity and event logs, update NIC drivers, test with `Get-SmbConnection`, and make sure SMB ports (445) aren't being interrupted by VPN/MTU settings or security tools.

## Common causes

- Network interruption between client and file server
- File server restarted or overloaded
- Firewall/antivirus resetting SMB
- NIC offload/driver problem
- SMB version or signing mismatch

## Quick fix

1. Test: `Test-NetConnection server -Port 445`
2. Update NIC drivers; try disabling large send offload
3. Review the server's SMBServer event log

## Detailed fix by platform

### Windows

1. 

```powershell
Test-NetConnection fileserver -Port 445
Get-SmbConnection
Get-WinEvent -LogName Microsoft-Windows-SMBServer/Operational -MaxEvents 20
```


## How to diagnose

1. **Port 445** — Reachable?
2. **Server** — Stable?
3. **Security software** — Resetting?

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Source: [WhatIsMyError](https://whatismyerror.com/errors/networking/smb-network-name-no-longer-available)