🎮 Common Scenario: Are you experiencing Error 300 while launching or installing Apex Legends? The solutions below directly address the system interactions specific to this application.
Restart the Affected Service: Press Win+R, type services.msc, and press Enter
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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 300, and generates a detailed HTML repair report.
What is Error 300?
Windows System Error Code 300, known as ERROR_OPLOCK_NOT_GRANTED, is a General System error that occurs during core Windows operations. The error indicates that: The oplock request is denied. When this error is encountered, the Windows operating system was unable to complete the requested operation within the system services subsystem. The error code 300 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_OPLOCK_NOT_GRANTED 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 core Windows operations is essential for effective troubleshooting.
Common Causes
- A system service has stopped or is unresponsive
- System files are corrupted or missing
- Insufficient system resources (memory, handles, threads)
- Driver or software conflict
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Read the full guide →Step-by-Step Solutions
- Press Win+R, type services.msc, and press Enter
- Look for any service showing 'Stopped' that should be running
- Right-click it → Properties → set Startup Type to Automatic
- Click Start, then click Apply → OK
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 "*300*" -or $_.Message -like "*ERROR_OPLOCK_NOT_GRANTED*"} | Format-List💡 Open PowerShell as Administrator, paste the command above, and press Enter.
Prevention Tips
- Keep Windows and drivers up to date
- Run sfc /scannow and DISM periodically
- Monitor Event Viewer for early warnings