cfprefsd high CPU on Mac? A misbehaving app, usually
cfprefsd using high CPU on your Mac is the preferences daemon, and it's almost always a badly behaved app or a corrupt preference file. Here's how to find the culprit and reset it safely.
cfprefsd is the preferences daemon that handles every settings read and write on your Mac. When it spikes, the cause is almost always another app misbehaving or a corrupt preference file, not the daemon itself. Here's how to find and fix it.
What cfprefsd does
It "provides preferences services for the CFPreferences and NSUserDefaults APIs." In plain terms: whenever an app or macOS reads or writes a .plist preferences file, cfprefsd does the file work, caches the values in memory, and keeps preferences consistent across processes. It runs as both a per-user instance and a root instance.
Why it's using high CPU
- A badly behaved app hammering preferences: often a recently installed or updated app repeatedly writing (or failing to finish writing) a setting.
- A corrupted
.plistfile it keeps trying and failing to parse: the classic cause of sustained high CPU and memory.
Is cfprefsd a virus?
No. It's a core part of macOS; you couldn't use your Mac without it. It's not malware, and you shouldn't try to permanently disable it.
What to do about it
- Find the offending app. Quit recently opened or updated apps one at a time;
cfprefsdusually calms down the moment the culprit closes. - Reset that app's corrupt preference. Delete its specific
.plistfrom~/Library/Preferences/(the app recreates a clean one) or use a tool like AppCleaner. (See how to completely uninstall a Mac app for finding an app's files.) - Reboot for system-wide churn; it restarts the daemon and clears transient load.
- Report recurring cases to the app's developer: it's a bug in their software, not in macOS.
What people get wrong
Because macOS caches preferences in memory via cfprefsd, hand-editing a .plist on disk while the owning app is running gets overwritten by the cached copy. Use defaults write, or quit the app first; otherwise your edit silently reverts, which baffles a lot of people.
Trace the spike to the app
cfprefsd at high CPU is a pointer to some other app behaving badly. Plumby shows live CPU with processes named plainly and the fix beside each, so you can connect the preferences churn to the app causing it and deal with the real source, measured from your Mac's real state, never estimated.
