What is Error 1784?
Windows System Error Code 1784, known as ERROR_INVALID_USER_BUFFER, is a RPC & Network error that occurs during Remote Procedure Call (RPC) and network communication. The error indicates that: The supplies user buffer is not valid for the requested operation. When this error is encountered, the Windows operating system was unable to complete the requested operation within the network services subsystem. The error code 1784 is returned by the GetLastError() function and provides developers with a specific identifier to diagnose the root cause of the failure. The symbolic name ERROR_INVALID_USER_BUFFER maps directly to this numeric code and is commonly referenced in Microsoft documentation, developer forums, and system logs. Understanding this error and its context within Remote Procedure Call (RPC) and network communication is essential for effective troubleshooting.
Common Causes
- System resource conflict: The supplies user buffer is not valid for the requested operation.
- RPC server is unavailable
- Network connectivity issues
- Firewall blocking required ports
Advanced Network Troubleshooting: DNS Flushes, Winsock Resets, and Adapter Fixes
The ultimate encyclopedia on resolving Windows network stack failures, TCP/IP corruption, Winsock errors, and DNS cache poisoning.
Read the full guide →Step-by-Step Solutions
- Open Command Prompt as Administrator
- Run: netsh winsock reset
- Run: netsh int ip reset
- Run: ipconfig /flushdns
- Restart your computer
Video Tutorials
Diagnostic Command
Run this PowerShell command to find related events in your system log:
Get-EventLog -LogName System -Newest 20 | Where-Object {$_.Message -like "*1784*" -or $_.Message -like "*ERROR_INVALID_USER_BUFFER*"} | Format-List💡 Open PowerShell as Administrator, paste the command above, and press Enter.
Prevention Tips
- Monitor network health regularly
- Document firewall rules
- Test connectivity after infrastructure changes