How to fix Error 687 on Windows 11

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Troubleshooting Guide: Error 687 – Secure Module Loading Notification on Windows 11

Why This Error Happens

Error 687 is not a critical failure but an informational message generated by the Windows DLL redirection and side-by-side (SxS) assembly system. It occurs when an application attempts to load a module (DLL) and Windows detects that a newer, more secure version of that module exists alongside an older, legacy version referenced by the app manifest. This typically happens with applications that haven’t been updated to explicitly target newer Windows API sets, causing the OS to flag a compatibility choice between the legacy path and the hardened system path.

Step-by-Step Resolution Guide

  1. Identify the Conflicting Module: Note the exact %hs module names referenced in the error dialog (e.g., comctl32.dll or a similar shared library). Check the application’s installation folder for a local copy of this file.

  2. Update the Application Manifest: Locate the application’s executable, right-click it, and check Properties > Compatibility. If the app has a .manifest file in its install directory (usually in C:\Program Files\[AppName]\), open it with Notepad and verify the dependency and assemblyIdentity tags point to the correct, updated version numbers rather than legacy ones.

  3. Run the Windows System File Checker: Corrupted system files can sometimes trigger this discrepancy. Open Command Prompt as Administrator and run:

   sfc /scannow

Follow this with:

   DISM /Online /Cleanup-Image /RestoreHealth

  1. Update the Software: Check the vendor’s website for a patch. Most modern software has resolved this by updating their manifests to align with Windows 11’s SxS assembly cache (C:\Windows\WinSxS) rather than shipping local outdated DLLs.

  2. Force the Application to Use the Secure Module: If prompted with the dialog interactively, select Yes to use the secure module unless you have a specific verified reason (like a legacy plugin incompatibility) to decline.

Alternative or Verification Steps

  • Verification: After applying the fixes, restart the application and monitor the Event Viewer (Windows Logs > Application) to confirm Event ID 687 no longer appears during the app’s startup sequence.
  • Alternative Fix: If the error persists and blocks functionality, try running the application in Compatibility Mode for an earlier OS version (right-click the .exe > Properties > Compatibility tab) as a temporary workaround while awaiting a vendor patch.