The Predictive Intelligence Engine
If you use an iPhone or a Mac, you have likely noticed that Siri frequently makes highly accurate suggestions. At 8:00 AM on a Tuesday, your Mac might automatically suggest opening Microsoft Teams or joining a specific recurring Zoom meeting. This predictive intelligence is powered by a background framework called CoreDuet (and its associated subsystem, the Knowledge daemon).
CoreDuet continuously monitors your behavior. It tracks exactly which applications you open, who you email, and what time of day you perform specific tasks, storing this telemetry in a massive, encrypted local database known as the knowledgeC.db cache. Over years of use, this database becomes massive.
If this database becomes corrupted, the symptoms are bizarre. Siri suggestions might become wildly inaccurate, the coreduetd background process might spike to 100% CPU usage as it desperately tries to parse a corrupted SQL table, or your Mac might experience severe lag when attempting to use the Handoff feature with your iPhone. To resolve these issues and reset Siri’s predictive intelligence to factory zero, you must purge the CoreDuet Knowledge cache via the Terminal.
Locating the Knowledge Database
Because CoreDuet tracks highly sensitive personal behavior, its database is strictly sandboxed within your specific user profile, not the global system root.
The primary directory is located at:
~/Library/Application Support/Knowledge/
Purging the Cache via Terminal
While this directory is in your user folder, attempting to drag it to the Trash via the Finder often fails because the coreduetd daemon holds a constant, aggressive lock on the SQLite files.
You must use the Terminal to orchestrate a precise shutdown and purge.
- Open the Terminal application.
- First, forcefully terminate the CoreDuet daemon to break its lock on the database:
killall coreduetd- Immediately execute the following command to recursively delete the entire Knowledge directory before the daemon has a chance to fully restart:
rm -rf ~/Library/Application\ Support/Knowledge/*(Note: The backslash is required to escape the space in the folder name).
Clearing the ContextStore (Optional)
CoreDuet also relies on a secondary, smaller cache called the ContextStore, which holds immediate, real-time device states (like whether you are currently driving or connected to a specific Wi-Fi network). If you are experiencing severe Handoff issues, you should purge this as well.
rm -rf ~/Library/Caches/com.apple.ContextStore/*The Rebuilding Phase
macOS relies heavily on coreduetd. The moment you killed the daemon, the system automatically began spinning up a new instance. When the fresh daemon boots, it will look for the knowledgeC.db file, realize it is completely missing, and instantly generate a fresh, empty SQLite database.
You have successfully destroyed the corrupted database and permanently resolved the associated CPU spikes. However, be aware that you have essentially given Siri “amnesia.” Your Mac will temporarily stop making intelligent app suggestions in Spotlight or the Notification Center. It will take a few weeks of normal usage for CoreDuet to re-learn your daily habits and rebuild its predictive models.