Smart App Control Has Blocked Part of This App

When Windows 11's Smart App Control displays the message "smart app control has blocked part of this app," it's indicating that the security feature has flagged the application as potentially unsafe due to either lacking a valid digital signature or being unfamiliar to Microsoft's security services. This protective mechanism, introduced with Windows 11, aims to prevent malicious or untrusted apps from running on your system.

Why This Happens

Smart App Control uses a cloud-based security service to evaluate applications before allowing them to run. The blocking typically occurs under several circumstances:

  • Unsigned applications : The app doesn't have a valid digital signature from a recognized publisher
  • Unknown or unfamiliar apps : Microsoft's security service cannot make a confident prediction about the app's safety
  • Invalid signatures : The app's digital certificate has expired or is improperly configured
  • Mark of the Web issues : In some cases, shortcuts (.lnk files) can trigger false positives even when the actual executable is safe

Interestingly, some users report that apps which previously worked fine suddenly get blocked after Smart App Control switches from "evaluation mode" to "on" mode without user intervention. This has affected legitimate software including Adobe Photoshop, emulators, and various streaming tools like Streamer.bot.

How to Fix the Issue

Turn Off Smart App Control

The most straightforward solution is to disable Smart App Control entirely:

  1. Open Windows Settings
  2. Navigate to Privacy & Security > Windows Security > App & Browser Control
  1. Click on Smart App Control settings
  2. Select Off and confirm your choice
  1. Restart your computer if prompted

Important note : Once you disable Smart App Control, you cannot re-enable it without performing a complete Windows reinstallation.

Alternative Approaches

  • Check Event Logs : Open Event Viewer and navigate to Application and Services Logs > Microsoft > Windows > CodeIntegrity > Operational to identify which specific files are being blocked (look for event IDs 3076 or 3077)
  • Contact the software vendor : Verify that your application has proper digital signing and request an updated version if necessary
  • Submit feedback to Microsoft : Use the Feedback Hub to report legitimate apps being incorrectly blocked, though responses may be limited

When Microsoft Suggests Disabling It

Even Microsoft support has recommended users disable Smart App Control when encountering persistent issues with legitimate software. While this may seem counterintuitive for a security feature, the current implementation has proven problematic for many users running verified applications from reputable sources.

TLDR : Smart App Control blocks apps that lack valid digital signatures or are unfamiliar to Microsoft's security systems. The quickest fix is disabling the feature through Windows Security settings, though this permanently prevents re-enabling it without a full Windows reinstall. Users report the feature frequently blocks legitimate software, with even Microsoft support recommending disabling it when issues persist. Information gathered from public forums or data available on the internet and portrayed here.