Smart App Control is a security feature in the Windows Security app that helps protect devices by preventing untrusted or potentially unsafe apps, services, and drivers from running. It evaluates executable files and drivers before they load, using digital signatures and Microsoft’s cloud‑based intelligence to determine whether a component can be trusted. If a file can’t be verified or isn’t properly signed, Smart App Control blocks it to reduce the risk of malware, unauthorized system changes, and other security threats.
If you see this message, it means that an app, service, or piece of hardware that you’re using has tried to load a driver, app, or other file that isn’t properly signed.
You might think of it like inviting someone to a enter a secure area and they bring a guest along. Even though you may be confident that the person you invited is safe, you’ll still want to confirm that their guest is as well.
Smart App Control knows you’re using the app safely, but it can’t make a confident prediction about the safety of another file the app opened. It checks the file’s signature to verify the publisher. If the file isn’t properly signed, Smart App Control blocks it. The functionality that depends on the file doesn’t work, but the rest of the app may continue to work fine.
As a result, whatever functionality that file was supposed to provide isn’t going to work, even though the rest of the app may continue to work just fine.
To see which driver, app, or other file is causing the blockage, select Learn more. If the popup disappears before you can select Learn more, you can check Protection history under Windows Security > Virus & threat protection and look for Smart App Controls or Blocked app entries. Â
