The Engine Behind Siri Suggestions
macOS is constantly monitoring your behavior in the background to provide intelligent suggestions. If you plug in your headphones every morning at 9:00 AM and open the Music app, macOS learns this pattern. Eventually, simply plugging in the headphones at 8:59 AM will cause the Music app icon to appear automatically in your Dock as a “Siri Suggestion.”
This behavioral intelligence is driven by a hidden background framework called Core Duet. Core Duet records massive amounts of metadata regarding your application usage, battery history, network connections, and sleep/wake cycles, storing it in a local SQLite database.
However, if this database becomes corrupted, or if it grows excessively large on a machine with a tiny 128GB SSD, it can cause severe system lag, battery drain, or wildly inaccurate Siri suggestions. To reset the machine’s behavioral learning, you must purge the Core Duet database using the Terminal.
Locating the Core Duet Database
The Core Duet database is stored in a hidden system directory that is protected by strict user permissions. You cannot simply drag the folder to the trash using the graphical Finder.
The databases are located in /var/db/CoreDuet/.
Purging the Database via Terminal
To clear the database, you must use the Terminal with elevated (sudo) privileges. You are not going to delete the directory itself; you are going to delete the contents within it.
- Open the Terminal application.
- Execute the following command to forcefully remove all files within the Core Duet knowledge directories:
sudo rm -rf /var/db/CoreDuet/*Press Enter, type your Mac’s administrator password (the characters will remain invisible), and press Enter again.
Warning: The rm -rf command is incredibly destructive if mistyped. Ensure you have the exact path before executing.
Restarting the Knowledge Daemon
Deleting the database files on the hard drive is only half the battle. The background daemon responsible for writing to that database (knowledge-agent or coreduetd depending on the exact macOS version) is still running in memory, holding onto the old corrupted data.
You must forcefully terminate the daemon to force it to drop its current memory state.
sudo killall coreduetdThe Rebuilding Process
After killing the daemon, macOS’s launchd system will instantly respawn a fresh, clean instance of the Core Duet agent. The agent will check the /var/db/CoreDuet/ directory, realize the SQLite databases are missing, and generate brand-new, empty database files.
Your Mac has essentially been given amnesia regarding your daily habits. Siri Suggestions will likely be blank or offer generic recommendations for a few days while the system quietly begins recording your application usage patterns from scratch.