How do I find out which application is using a Legacy Extension?

K_Snyders wrote:

I'm running macOS Monterey (12.3.1). The Legacy Extension warning message mentions the manufacturer of the extension (Marvel Semiconductors Inc.) but does not mention which application is using it. How do I find out which application is using this extension?

You do not say what exact Mac is this...

M1—Change security settings on the startup disk of a Mac with Apple silicon - Apple Support

The current stable release of Monterey including bug fixes, is macOS 12.4

Keep your Mac up to date - Apple Support

Keep your Mac up to date - Apple Support

Typically you have to do nothing, Developer will issue updates.

>(Option key) System Information > Extensions

>(Option key) System Information > Applications look for 32-bit apps (unsupported)

—see if there is "Media Key Enabler" (?) ...Marvel Semiconductors Inc

—Several LaCie  programs (LaCie RAID Manager) are impacted by this macOS feature. Please see below for the list of impacted applications....Marvel Semiconductors Inc

Lacie external drive — https://www.lacie.com/support/kb/system-extension-blocked-alert-during-software-installation-007815en/

ref: system software from developer marvell se… - Apple Community

"Marvell Semiconductor Inc" was blocked f… - Apple Community

System Preferences>Security & Privacy to enable the “Marvell Semiconductor Inc” kernel extension.

From the Terminal.app you can try for a list of non-Apple kext:

kextstat -l | grep -v com.apple

The below method should present both Applications Installed as well as Extensions also installed with the specific path to its' location on the drive.

Perhaps between the inventory of Installed Applications and Extensions, the User and we can help identify the troublesome Application and / or Extension.

Understand, we are all working Remotely from all around the world. 

Therefore, we do not have the On-Hands experience the User ( you ) has with this computer.

The next best thing for us to having an actual On-Hand experience  with this computer is to follow the steps below

Download the Application Etrecheck directly from a well Respected ASC Contributor. And Safe to use.

The application is free or paid from added features. 

Run the application with Full Disc Access ( Security & Privacy - Full Disc Access ).

It will take a Snap Shot -  both the hardware and software.

 The Report will Not Reveal Any Personal Information. 

Post back the Full Report - copy and paste - using the Additional Text Icon ( 3rd Icon to last )

We can have a look at the report for possible issues and may have possible suggestions to resolve the issues.

About system extensions and macOS - Apple Support (CA)

If you get an alert about a system extension

You may see an alert on your Mac that says that a program loaded or tried to load a system extension signed by the developer of that extension. 

• The alert may ask you to open Security & Privacy preferences to allow the extension. You may also need to restart your Mac. 
• The alert may ask you to contact the developer for support because the extension needs to be updated or will be incompatible with a future version of macOS.
• The alert may inform you that it will damage your computer and has been blocked.

On a Mac with Apple silicon, you may first need to use Startup Security Utility to set the security policy to Reduced Security and select the “Allow user management of kernel extensions from identified developers” checkbox.

System administrators can also use Mobile Device Management (MDM) to manage legacy system extensions. 

If necessary, please contact the developer to learn whether an updated version of their software is available or planned. They may also be able to explain how to remove or disable the extension, and the consequences of doing so.

If necessary, please contact the developer to learn whether an updated version of their software is available or planned. They may also be able to explain how to remove or disable the extension, and the consequences of doing so.