How to Fix Fix Error 0x8007003A — Network Server No Longer Available on Windows
Getting error 0x8007003A when accessing network files? "The specified server cannot perform the requested operation"? File copy over network fails? Server connection dropping mid-transfer? Fix this network server availability error.
Symptoms
You might be experiencing this problem if you notice:
- •File copy to/from network share fails with 0x8007003A
- •Network drive shows files but transfer fails mid-way
- •Large file transfers always fail at random points
- •Accessing network folders intermittently throws this error
- •Print jobs to network printer fail with this code
- •VPN file access drops with this error
Common Causes
- ⚠Network connection unstable or dropping packets
- ⚠SMB session timeout during large file transfers
- ⚠Server going to sleep or entering power saving mode
- ⚠Network adapter power management disconnecting during idle
- ⚠Firewall or router dropping long-lived connections
- ⚠WiFi signal strength too weak for sustained transfers
Solutions
Solution 1: Fix Network Adapter Power Management
- 1Prevent Windows from turning off the network adapter:
- 2Device Manager → Network adapters
- 3Right-click your adapter → Properties → Power Management tab
- 4Uncheck: "Allow the computer to turn off this device to save power"
- 5Also check Advanced tab:
- 6Find "Energy Efficient Ethernet" → Disable
- 7Find "Power Saving Mode" → Disable
- 8Find "Wake on Magic Packet" → doesn't matter, leave as-is
- 9Apply to both WiFi and Ethernet adapters
- 10Do this on BOTH the client and server if possible
Solution 2: Increase SMB Timeout and Optimize Transfer
- 1Increase the SMB session timeout:
- 2Registry on client PC:
- 3HKLM\SYSTEM\CurrentControlSet\Services\LanmanWorkstation\Parameters
- 4Add DWORD: SessTimeout = 600 (default is 60 seconds)
- 5This gives the server 10 minutes to respond
- 6Also increase keep-alive:
- 7Add DWORD: KeepConn = 3600 (seconds to keep idle connection)
- 8For large file transfers:
- 9Use robocopy instead of File Explorer drag-and-drop:
- 10robocopy \\server\share C:\local /E /Z /R:3 /W:10
- 11/Z enables restartable mode — resumes interrupted transfers
- 12Restart PC after registry changes
Solution 3: Fix Server and Network Stability
- 1If server is going to sleep:
- 2On the file server: disable sleep in Power Options
- 3Control Panel → Power Options → Change plan settings → Never sleep
- 4If WiFi transfers failing:
- 5Use Ethernet cable for large transfers (much more reliable)
- 6If WiFi only: move closer to router or use 5GHz band
- 7Check for network congestion:
- 8Other devices may be saturating bandwidth
- 9Pause streaming/downloads during large file transfers
- 10If using VPN:
- 11VPN adds latency — increase timeouts further
- 12Split-tunnel VPN if file server is on local network
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