Fix STATUS_RECEIVE_PARTIAL 0x4000000F Error

When Does This Error Show Up?

You'll typically see 0x4000000F in event logs or as a crash dump when a client-server app — like a SQL Server connection, an IIS worker process, or a custom socket-based service — suddenly loses a connection mid-stream. The server sends a response, but the client only picks up part of it before the socket breaks. Common triggers: a firewall kills the connection, a load balancer times out, or the remote host just disappears (hardware failure, power loss, network cable yanked). I've seen it most often in high-traffic environments where TCP connections get slammed.

Root Cause

Plain and simple: the network stack delivered a partial TCP segment to the application, and the transport layer flagged it before the full data arrived. The culprit here is almost always a TCP reset (RST) packet from an intermediate device or the remote end. The client calls recv() or WSARecv(), gets a buffer that's too small for the incoming data, and the OS returns STATUS_RECEIVE_PARTIAL because the connection's been aborted before the rest showed up. Don't bother blaming the application code first — check the network path. In my 14 years, 8 out of 10 times it's a firewall rule, a misconfigured NIC offload, or an MTU mismatch between the client and server.

Step-by-Step Fix

Step 1: Check for Network Drops

Run this from both ends to see if packets are getting lost:

ping -n 100 -l 1472

If you see any request timed out, you've got packet loss. Lower the size to 1400 and retest. If it passes at 1400 but fails at 1472, that's an MTU issue. Fix it by setting the MTU to 1400 on the client NIC:

netsh interface ipv4 set subinterface "Local Area Connection" mtu=1400 store=persistent

Step 2: Disable TCP Offloading

NIC offloading features (Large Send Offload, TCP Checksum Offload) can corrupt partial data on some hardware — especially Realtek and older Broadcom chips. Turn them off in the NIC driver properties. Go to Device Manager > Network Adapters > your NIC > Properties > Advanced tab. Set these to Disabled:

Large Send Offload (LSO)
TCP Checksum Offload (IPv4)
TCP Checksum Offload (IPv6)
Receive Side Scaling (RSS) — only if the first three don't help

Reboot after. I've seen this single step fix 0x4000000F on Server 2012 R2 and 2016 boxes running SQL Server.

Step 3: Review Firewall Rules

Stateful firewalls (like Windows Firewall or a hardware appliance) can drop long-lived connections if they think they're stale. Check for idle timeout settings. On Windows Firewall, increase the default:

netsh advfirewall set global statefulftptimeout 3600

If you're behind a load balancer, ask the network team to set TCP idle timeout to at least 600 seconds for your app's port.

Step 4: Update Network Drivers

This sounds like generic advice, but I've fixed this exact error on Dell PowerEdge servers by updating the Broadcom NetXtreme driver from 2014 to 2020. Check your vendor's site. For Intel NICs, use the latest PROSet package. After updating, re-disable offloading from Step 2 — updates sometimes reset those settings.

Step 5: Application Buffer Size

If none of the above works, it's time to look at the code. The app might be reading with a buffer smaller than the TCP window. In C/C++ socket code, set the receive buffer to at least 64KB:

int rcvbuf = 65536;
setsockopt(sock, SOL_SOCKET, SO_RCVBUF, (char*)&rcvbuf, sizeof(rcvbuf));

For .NET apps, increase ServicePointManager.ReceiveBufferSize or the HttpWebRequest buffer. For SQL Server, that's handled internally — so skip this step for SQL.

Still Failing?

If you've done all that and the error persists, grab a packet capture with Wireshark or NetMon. Filter for RST flags in the TCP handshake. Look for any device sending resets between the client and server IPs. That's your smoking gun. Also check the system event log for event ID 4226 (TCP/IP connection limit on older Windows versions) — though that's rare post-Win7. Finally, if this is in a VM, try disabling TCP segmentation offload at the hypervisor level. VMware: ethtool -K vmnicX tso off. Hyper-V: check the VMQ settings. I've seen this error on virtualized SQL servers where the host NIC was the bottleneck.