⚠️ 2 verified solutions available for Error 1151 — Last updated 2026-03-13
Error 1151 📋

Fix ERROR_SINGLE_INSTANCE_APP — Windows Error Code 1151

Error 1151 (ERROR_SINGLE_INSTANCE_APP) is a Windows Configuration error that occurs when the specified program is not a windows or ms-dos program.. This guide provides step-by-step solutions to resolve this issue.

🏷️ Code: 1151 📛 ERROR_SINGLE_INSTANCE_APP 📅 Updated: 2026-03-13 ⏱️ 2 Solutions

🎮 Common Scenario: Are you experiencing Error 1151 while launching or installing Valorant? The solutions below directly address the system interactions specific to this application.

⚡ Quick Fix

Restore Registry from Backup: Press Win+R, type rstrui.exe, press Enter

👇 See all 2 solutions below

The Ultimate Auto-Fix Script

Download our advanced, custom-built Smart Diagnostic Script (.bat). It safely creates a System Restore Point, applies targeted fixes based on advanced diagnostics for Error 1151, and generates a detailed HTML repair report.

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📑 Table of Contents
What is Error 1151? Common Causes Step-by-Step Solutions Prevention Tips Related Errors

💡 What is Error 1151?

Windows System Error Code 1151, known as ERROR_SINGLE_INSTANCE_APP, is a Configuration error that occurs during system configuration and registry. The error indicates that: The specified program is not a Windows or MS-DOS program. When this error is encountered, the Windows operating system was unable to complete the requested operation within the configuration management subsystem. The error code 1151 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_SINGLE_INSTANCE_APP 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 system configuration and registry is essential for effective troubleshooting.

⚠️ Common Causes

  • Registry entries are corrupted
  • Config files are missing or malformed
  • A recent update changed system settings
  • Software version incompatibility
📚 Comprehensive Guide

Diagnosing Memory Management and RAM Faults in Windows 10 & 11

An encyclopedia on diagnosing physical RAM defects, virtual memory (paging file) corruption, and resolving MEMORY_MANAGEMENT BSODs.

Read the full guide →

✅ Step-by-Step Solutions

1 Restore Registry from Backup
  1. Press Win+R, type rstrui.exe, press Enter
  2. Select a restore point before Error 1151 (ERROR_SINGLE_INSTANCE_APP) started
  3. Follow the wizard to restore system configuration
  4. Restart your computer
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2 Reset Application Settings
  1. Open Settings → Apps → Apps & Features
  2. Find the app → Advanced options → Reset
  3. This restores default configuration without uninstalling

🎬 Video Tutorials

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💻 Diagnostic Command

Run this PowerShell command to find related events in your system log:

Get-EventLog -LogName System -Newest 20 | Where-Object {$_.Message -like "*1151*" -or $_.Message -like "*ERROR_SINGLE_INSTANCE_APP*"} | Format-List

💡 Open PowerShell as Administrator, paste the command above, and press Enter.

🛡️ Prevention Tips

  • Back up registry before editing
  • Use built-in tools, not manual edits
  • Document all system configuration changes
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Last updated: 2026-03-13
📖
Based on Official Microsoft Documentation
Solutions Tested on Windows 10 & 11
Error codes sourced from Microsoft Win32 SDK. Updated 2026-03-13.
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