How to fix Error 100 on Windows 11

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Windows 11 Error 100: “Cannot Create Another System Semaphore”

Why This Error Happens

This error occurs when the Windows kernel exhausts its available pool of system semaphore handles, typically due to a resource leak caused by a misbehaving driver, service, or application that creates semaphores without properly releasing them. It can also result from a depleted non-paged memory pool, corrupted system files affecting the Object Manager, or an accumulation of orphaned handles from a process that crashed without cleanup. Over time, as available system resources dwindle, the OS is unable to allocate new synchronization objects, triggering Error 100.

Step-by-Step Resolution Guide

  1. Identify the Resource-Hogging Process
    Open Task Manager (Ctrl+Shift+Esc) → Details tab → right-click column headers → Select Columns → enable Handles. Sort by this column to identify any process consuming an abnormally high number of handles (typically in the thousands).

  2. Restart the Offending Service or Application
    If a specific service is identified, restart it via Services.msc (Win+R → services.msc) rather than rebooting the entire system. Right-click the service → Restart.

  3. Check and Increase System Resource Limits
    Open Registry Editor (regedit) and navigate to:
    HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Session Manager\Memory Management
    Verify the PagedPoolSize and NonPagedPoolSize values are set to 0 (which allows Windows to auto-manage them dynamically). If they are set to a fixed low value, adjust or remove the override.

  4. Run System File Checker and DISM
    Open Terminal (Admin) and run:

   sfc /scannow

Followed by:

   DISM /Online /Cleanup-Image /RestoreHealth

This repairs corrupted system files that may be mishandling kernel object creation.

  1. Update Drivers via Device Manager
    Outdated or buggy drivers (especially storage, GPU, or network drivers) are common culprits. Open Device Manager, check for warning icons, and update drivers via Windows Update → Optional Updates or directly from the manufacturer’s website.

Alternative or Verification Steps

  • Verify the Fix: Use Performance Monitor (perfmon) and add the counter Object: Semaphores under the Objects category to confirm handle counts remain stable over time instead of climbing indefinitely.
  • Alternative Fix: If the issue persists, perform a clean boot (via msconfig → Selective Startup) to isolate whether a third-party startup application is causing the semaphore leak, then uninstall the offending software.