What, Why & How: StandaloneUpdate (Not Responding) in Activity Monitor and using almost all our %CPU?

StandaloneUpdate is typically associated with system updates and may indicate that there's a task related to updates that has encountered a problem or is stuck. When this process isn't responding and is using a lot of CPU, it can lead to overall sluggishness and unresponsiveness.

To address this issue, you can try a few troubleshooting steps:

Firstly, attempt to restart your iMac. Sometimes, a simple restart can clear out temporary glitches and refresh system processes. Monitor whether the StandaloneUpdate process behaves normally after the restart.

Check for any available system updates by going to the Apple menu > System Preferences > Software Update. Install any pending updates to ensure your macOS is up-to-date.

Consider resetting the NVRAM (Non-Volatile Random-Access Memory) or PRAM (Parameter RAM). Restart your iMac and immediately hold down the Option, Command, P, and R keys simultaneously until you hear the startup sound again.

Use the Activity Monitor to identify any other processes consuming an unusually high amount of CPU resources. Investigate these processes further and terminate any unnecessary ones.

Run Disk Utility to check for and repair any disk errors or permissions issues. Open Disk Utility from the Applications > Utilities folder, select your startup disk, and choose First Aid to perform a disk check.

Monitor your iMac's performance over time to see if the issue persists or improves. If the StandaloneUpdate process continues to cause high CPU usage and unresponsiveness, consider seeking further assistance from Apple Support or consulting with a professional technician.

By following these steps, you can hopefully diagnose and resolve the performance issues associated with the StandaloneUpdate process on your iMac running Sonoma 14.4.1.