How to fix Error 105 on Windows 11

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Why This Error Happens

Error 105 occurs when a Windows process or service loses control of a named semaphore—a synchronization object used to manage access to shared resources between multiple threads or processes. This typically happens when the original owning process crashes, is forcibly terminated, or times out before properly releasing the semaphore handle, leaving it in an orphaned state. Corrupted service dependencies, outdated drivers, or conflicts between multiple instances of an application trying to access the same shared resource can also trigger this abandonment.

Step-by-Step Resolution Guide

  1. Identify the source process: Open Event Viewer (eventvwr.msc) → navigate to Windows Logs > Application or System, filter by Event ID 105, and check the “Source” field to determine which application or service triggered the error.

  2. Restart the affected service cleanly:

  • Press Win + R, type services.msc, and press Enter.
  • Locate the service tied to the error (e.g., Print Spooler, SQL Server Agent, or a third-party backup/sync tool).
  • Right-click → Stop, wait 10 seconds, then right-click → Start.
  1. Clear orphaned handles via reboot in Safe Mode:
  • Go to Settings > System > Recovery > Advanced startup > Restart now.
  • Select Troubleshoot > Advanced options > Startup Settings > Restart, then press 4 for Safe Mode.
  • This forces Windows to release all held semaphores and handles cleanly on the next normal boot.
  1. Update or reinstall the affected application’s drivers/dependencies:
  • Open Device Manager (devmgmt.msc) and update drivers for any hardware tied to the failing service (common with storage or print drivers).
  • If it’s a third-party app, uninstall it via Settings > Apps > Installed apps, then reinstall the latest version from the vendor.
  1. Run System File Checker and DISM to repair corrupted system components that manage synchronization objects:
   sfc /scannow
   DISM /Online /Cleanup-Image /RestoreHealth

Run these in an elevated Command Prompt or PowerShell window, then restart your PC.

Alternative or Verification Steps

  • Verify the fix: Reopen Event Viewer after reproducing the original task (e.g., printing, running the backup job) and confirm no new Event ID 105 entries appear.
  • Alternative fix: If the error persists and is tied to a specific third-party application, check the vendor’s website for a patch—this error is frequently resolved in updated builds that handle semaphore release more gracefully during unexpected shutdowns.