What is Triald on macOS, And Why Is It A System Hog

Mad Machine
2 min readApr 23, 2022

This morning I plugged in my MacBook Pro and started to use my computer for web browsing but noticed my mouse cursor was laggy — choppy. I opened the Activity Monitor utility app to view the apps and the resources they’re consuming.

One app, triald, was consuming the most amount of CPU cycles. Not knowing what it was, I did a web search to find out more about it. This is what I learned.

  • It’s a background service that often glitches and causes problems for many users — stealing CPU cycles, taking a considerable amount of disk space in ~/Library/Trial, and taking up space in Time Machine backups. My system uses almost 700MB of space, but some people have reported much larger space than that.
  • It was introduced in Big Sur, but it’s also in Monterey (I’m using Monterey version 12.3.1).
  • Some reports suggest that this is only activated on Macs that participate in Apple’s Beta Program, but I’m not participating, so that’s not true.
  • Triald will respawn if killed.
  • Triald normally doesn’t cause any problem but occasionally glitches.
  • Triald is in the SSV (signed system volume), so it cannot be disabled.
  • Most of the files I see have Siri in the name. On my system, Siri is enabled. Because I don’t use Siri on my Mac, I will disable it and see if this alleviates this problem.
  • Trial (triald) has CloudKit entitlements and often communicates over CloudKit, from where it appears to get Experiments and upload its data.
  • Triald is currently undocumented

This is the size of my triald directories

du -sh ~/Library/Trial/*
52K /Users/fongyang/Library/Trial/NamespaceDescriptors
696M /Users/fongyang/Library/Trial/Treatments
4.0K /Users/fongyang/Library/Trial/schemaVersion.txt
81M /Users/fongyang/Library/Trial/v6

Here are more discussions about triald :



Because most of what’s in ~/Library/Trial has Siri in the name, I will disable Siri because I don’t need Siri on my laptop.

If anyone has a working fix or knows what it is, let me know.

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Mad Machine

I’m a DevOps engineer, but I love to tinker with all kinds of technologies.