Hi 고,
RuntimeBroker.exe is a legitimate Windows file located at C:\Windows\System32\RuntimeBroker.exe, which is used by Store apps like Photos, Paint 3D, etc.
You can add it as an exception to the Controlled folder options to prevent the notification.
- Open the Windows Security app.
- Select the Virus & threat protections
- Select Manage ransomware protection.
- Under the Controlled folder access section, select Allow an app through Controlled folder access
- Select Add an allowed app and add "C:\Windows\System32\RuntimeBroker.exe" to the exceptions.