WhySlow
Understand before you act.
Read the explanation. See the trade-off. WhySlow asks before every fix, including quitting an app.
Your Mac is slow.
Let’s find out why.
A busy app. A hundred browser tabs. Something called kernel_task.
Get an actual answer. Then a way forward.
Free to understand. $10 to fix.
Overview
Understand what’s happening on your Mac.
Choose a situation. See the cause. Preview a fix.
Click around. It’s a working preview.Sample data only. Nothing on your Mac is accessed.
Made for macOS 15+Apple silicon & IntelNo account to get startedPay once or yearly
Numbers are easy.
Answers are better.
Activity Monitor tells you what’s running. WhySlow helps you understand what it means and what to do next.
THE NAME YOU WERE ABOUT TO GOOGLE
kernel_taskCPU248.6%
A big number. A mysterious name.
Should you be worried?
Leave it runningYour Mac is keeping
Your Mac is keeping
itself cool.
This is part of macOS. When your Mac gets hot, it limits how much processing power other apps can use. Quitting it won’t help.
Here’s what you can doThe whole picture.
One small app.
From background helpers to a sluggish connection, see the pieces that Activity Monitor leaves you to figure out.
An answer, right when you need it.
The most likely cause, the signals behind it, and a useful next step.
Get to know the names behind the numbers.
Apps and helpers grouped together, with clear Safe to quit, Review and Leave it verdicts.
“Background Items Added.” Finally explained.
Find which app a helper belongs to and whether it is running.
Your Mac, or your connection?
See Wi-Fi signal, bandwidth-hungry apps and an on-demand speed test.
A new Mac? Start with the evidence.
CPU and memory history help you understand what actually holds your Mac back.
From “why?”
to “got it.”
Take a quick look through WhySlow’s diagnosis, process explanations, background items, internet checks and usage history.
Or take the interactive demo for a spin ↗Product walkthrough · 20 seconds · No audio
A little help.
Always your call.
Understanding your Mac should feel reassuring.
So every action starts with you.
System processes stay protected.
WhySlow explains macOS processes without quitting them. It never deletes your files.
Your activity stays on your Mac.
Process data, tab details and usage history stay local. No account is needed to start.
The full privacy story ↗Understand for free.
Fix for $10.
Try it on your own Mac first.
Upgrade only when a one-click fix is useful.
Get the full picture.
$0 free, always
Answers shouldn’t be behind a paywall.
- Live diagnosis, in plain English
- Every process explained
- Background items and internet checks
- Usage history and upgrade advice
No card. No account. Just answers.
Do something about it.
ONCE OR YEARLY$10 once, or per year
Everything free, plus one-click fixes.
- Quit an app and its helpers together
- Close duplicate tabs and merge windows
- Rebuild a stuck Spotlight index
- Use on up to 3 of your Macs
Once: fixes in versions released in the next 12 months. Yearly: fixes in every new version. 30-day refunds.
Already have a license? Recover your key
A few good
questions.
Something else on your mind?
Say hello ↗
What can I do for free?
All diagnosis and explanations are free, including processes, background items, internet checks, and usage history. A $10 license unlocks one-click fixes, once or yearly.
Is this actually checking my Mac?
The website preview uses example data only. Download the native Mac app to see what is happening on your own Mac.
Will it make my Mac faster?
WhySlow helps you find the cause of a slowdown and choose a useful next step. Results depend on the cause. Sometimes the best answer is to leave macOS alone while it finishes its work.
Can it quit something important?
System processes such as kernel_task and WindowServer are protected. WhySlow asks before every action. Save your work before quitting an app.
Which Macs are supported?
WhySlow requires macOS 15 or later and supports both Apple silicon and Intel Macs.
What happens after I buy?
Your license key appears after checkout and is also sent by email when email delivery is available. Open the activation link or paste your key in WhySlow. One license works on up to three of your Macs.
Less guessing.
More getting on with it.
Find out why your Mac is slow. Start for free.
Get WhySlow for MacmacOS 15+ · Apple silicon & Intel