How to Fix Fix Error 0x8007003E — Network Data Fault on Windows
Getting error 0x8007003E during network operations? Network data transfer fault? File copy over network failing with data error? Remote connection data corruption? Network stream interrupted? Fix this network data fault error.
Symptoms
You might be experiencing this problem if you notice:
- •File transfers over network fail with 0x8007003E
- •Large file copies to network share interrupted
- •Error occurs mid-transfer, not at start
- •Downloading files from network fails with data fault
- •SMB file operations return this error intermittently
- •Network backup software reporting data errors
Common Causes
- ⚠Network packet corruption during transfer
- ⚠Faulty network cable or switch port
- ⚠Network adapter driver bug causing data corruption
- ⚠SMB signing mismatch causing validation failures
- ⚠MTU size causing fragmentation and data loss
- ⚠Network buffer overflow on slow or congested links
Solutions
Solution 1: Fix Network Connection Quality
- 1Test basic connectivity:
- 2ping <server-ip> -t -l 1472
- 3Watch for packet loss or high latency
- 4Any loss > 0% indicates network issues
- 5Test with different MTU sizes:
- 6ping <server-ip> -f -l 1472 (standard MTU)
- 7If this fails: lower the number until it works
- 8Set correct MTU:
- 9netsh interface ipv4 show subinterfaces
- 10netsh interface ipv4 set subinterface "Ethernet" mtu=<working-value> store=persistent
- 11Check physical connections:
- 12Try a different ethernet cable
- 13Try a different switch port
- 14For WiFi: move closer to access point or use ethernet
Solution 2: Fix Network Adapter and SMB Settings
- 1Update network adapter driver:
- 2Device Manager → Network adapters
- 3Right-click your adapter → Update driver
- 4Or download latest from manufacturer website
- 5Disable problematic network offloading:
- 6Device Manager → Network adapter → Properties → Advanced
- 7Disable: "Large Send Offload V2 (IPv4)"
- 8Disable: "Large Send Offload V2 (IPv6)"
- 9Disable: "TCP Checksum Offload (IPv4)" — test
- 10Fix SMB settings:
- 11PowerShell as Admin:
- 12Set-SmbClientConfiguration -RequireSecuritySignature $false -Confirm:$false
- 13Or on the server:
- 14Set-SmbServerConfiguration -RequireSecuritySignature $false -Confirm:$false
- 15Note: disabling signing reduces security — for troubleshooting only
- 16Re-enable after identifying the root cause
Solution 3: Use Alternative Transfer Methods
- 1If SMB file copy keeps failing:
- 2Try robocopy with retry and restartable mode:
- 3robocopy "source" "\\server\share\dest" /Z /R:5 /W:5
- 4/Z = restartable mode (resumes after interruption)
- 5/R:5 = retry 5 times per file
- 6/W:5 = wait 5 seconds between retries
- 7For very large files:
- 8Consider splitting: split the file before transfer
- 9Or use a different protocol:
- 10FTP/SFTP instead of SMB
- 11Or copy to USB drive and transfer physically
- 12If only one server is affected:
- 13Check the server's network adapter and disk health
- 14Event Viewer on server may show disk or network errors
- 15chkdsk on the share drive to fix file system errors
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