WSAEINPROGRESS (0x00002734) – A blocking operation is executing
Your app says a blocking operation is stuck. This usually means a socket call got interrupted or a Winsock lock is held up. I'll walk you through the quick fix first.
Quick Fix – 30 seconds: Kill the stuck socket
Most times this error means a previous network call never finished. Open Command Prompt as admin and run:
netstat -ano | findstr :PORTReplace PORT with the actual port your app uses. Look for a line with state ESTABLISHED or TIME_WAIT. The last column is the PID. Then run:
taskkill /PID [the PID number] /FThat kills the hanging process. Restart your app. Had a client last month whose print server locked up because an old print spooler socket was stuck. This killed it instantly.
If you don't know the port, run netstat -ano and look for any socket in TIME_WAIT or CLOSE_WAIT that matches your app's executable name. Check Task Manager for the PID if needed.
Moderate Fix – 5 minutes: Reset Winsock and flush DNS
If killing the socket didn't work, the Winsock catalog might be corrupt. I've seen this after a failed VPN install or a bad network driver update. Run these commands as admin:
netsh winsock reset
netsh int ip reset
ipconfig /flushdnsReboot after. Winsock reset wipes custom LSP settings but fixes most socket errors. On Windows 11, I've had to do this after a Cisco AnyConnect uninstall left junk behind.
Also check if your antivirus or firewall is blocking the port temporarily. Disable them for 30 seconds and try again. If the error goes away, add a rule to allow your app through. Don't leave the firewall off.
Advanced Fix – 15+ minutes: Check for driver conflict or app bug
Still getting the error? Time to dig deeper. This error code (0x00002734) means WSAEINPROGRESS — a blocking operation is already running on that socket. In older Windows versions (7, 8), some apps called WSAStartup multiple times and caused this. On Windows 10/11, it's rarer but still happens with poorly written socket code.
First, update your network adapter driver. Go to Device Manager, find your network adapter, right-click and choose "Update driver". If that doesn't work, download the latest driver from the manufacturer's site — don't rely on Windows Update for this. I had a client using a Realtek PCIe GbE controller where the stock driver from 2019 caused exactly this error under heavy load. Updated to the 2023 driver, problem gone.
Second, run sfc /scannow and DISM /Online /Cleanup-Image /RestoreHealth to repair system files. Corrupt Winsock DLLs (like ws2_32.dll) can trigger this.
Third, if this is a custom app you're developing, check your code. You cannot start a second blocking operation on the same socket while one is pending. Use non-blocking sockets or select() to check readiness. In C++, wrap socket calls with error handling for WSAEWOULDBLOCK — that's the non-blocking equivalent, but the same root cause.
Finally, if nothing else works, try a clean boot. Disable all startup items and non-Microsoft services via msconfig. Re-enable them one by one until the error returns. I've seen third-party firewall software (ZoneAlarm, Comodo) inject LSP layers that hold sockets open.
One last thing: check the Windows Event Viewer under Applications and Services Logs -> Microsoft -> Windows -> Winsock for any operational events. That log is rarely checked but can show LSP load failures.
If you're still stuck after all this, the app itself might have a bug. Contact the vendor and show them the error with a network capture from Wireshark. They'll see exactly which socket call failed.
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