Unapproved caller. SecurityAgent may only be invoked by Apple software

Hi joven97,

Thanks for using Apple Support Communities. Let's look into this together. Are you seeing this alert message appear on the login screen when you first start your Mac and attempt to log in?

If so, let us know what happens when you start your Mac in safe mode. Safe mode verifies startup directories, and prevents login items from loading, so it's a great way to isolate unexpected software behavior.

The following Knowledge Base article has the steps to guide your through the process of starting up and testing in safe mode:

How to use safe mode on your Mac

If the issue is resolved while in safe mode, perform a standard restart to exit safe mode, and let us know if it also resolves the behavior in a normal startup.

If not, you'll want to check for incompatible login items by following these steps:

If your Mac has a blue screen or other startup problems

We're here for you if you've got any questions.

Have a great day!