MacBook gets hot, runs slow or the fan is loud: causes

A MacBook that gets warm is not necessarily broken: heavy work produces heat. It becomes a problem when it gets hot while you are doing little, when the fan roars all the time or when the Mac feels slow and sticky. Below you can work out whether it is software, dirt or a part at the end of its life.

Blue Apple repairs MacBooks at Rijnstraat 76-H in Amsterdam. More about what we offer per model is on the MacBook repair page.

First, see what is running

• Open Activity Monitor. Sort by processor use. An app or process that constantly asks for a lot is often the cause. A process called kernel_task with high use usually means macOS is holding the Mac back because it is too hot, not that kernel_task itself is the problem.
• After an update or on a new Mac. Spotlight and Photos then index in the background for a while, which makes the Mac warm and slow. That passes by itself if you leave it on.
• Browser and tabs. A browser with dozens of tabs, or a page with a script that runs wild, can keep a Mac completely busy.
• Startup items and full storage. Programs that start at login and storage that is nearly full make a Mac noticeably slower.

Simple things that often help

1. Restart and update. A Mac that has been on for weeks collects clutter in memory. Install pending updates as well.
2. Clear out. Make sure there is enough free space on the storage and remove programs you do not use, including from Login Items and extensions.
3. Give it air. Use it on a hard, flat surface and not on a bed, cushion or lap where the vents get blocked. On a MacBook with a fan they are at the hinge and underneath; an Air with an Apple chip has no fan and gives off heat through the case.
4. Run Apple Diagnostics. On a Mac with an Apple chip, hold the power button until the startup options appear and press Command + D; on an Intel Mac hold D while it starts. You get a result or a reference code that can point to a hardware problem.

When it is hardware

• The fan runs all the time, or makes a grinding or whining sound. Dust, a worn bearing or a blocked fan.
• The device also gets hot when nothing is running. Then heat removal has got worse, or a part is drawing more power than it should.
• An older Mac, especially with an Intel processor. The thermal paste between processor and cooler becomes less effective after years. Applying it again can make a big difference.
• A swollen or worn battery. It gets warm while charging and can swell. That is not something to wait on: read when to replace a MacBook battery.
• The storage. An SSD that throws errors makes programs freeze and the spinning wheel appear. That is not a heat problem but feels like one.

What you had better not do

• Do not open your MacBook to blow out the fan yourself unless you know how: the battery is connected to the board and cables are fragile.
• Do not install programs that promise to 'control' the fan or 'clean' the Mac.
• Do not keep working on a MacBook that gets hot for no reason: heat wears the battery and other parts.

What we do at Blue Apple

We check the fans and the airflow, measure what the processor and battery do and see whether the storage throws errors. That usually makes clear whether it is a matter of cleaning or replacing a part, a battery, or something that needs to be set up again. Then we explain what is needed. You can find the repairs per model on the MacBook page.

Frequently asked questions

Is it normal for a MacBook to get warm?

Yes, during heavy work such as editing video, gaming or video calls. It is not normal if it gets hot while you are doing little, or if the fan runs at high speed all the time.

Why does my MacBook Air have no fan?

An Air with an Apple chip is designed to be cooled passively. Under heavy load it slows itself down, which you notice as a slower Mac rather than as noise.

Can I clean the fan myself?

Only by opening the device, and we do not recommend that without experience. A fan that makes noise is better looked at.

My MacBook is slow. Does anything really need repairing?

Often not: tidying up, updating and a restart usually help. Only when that does nothing and you have symptoms such as heat, noise or freezes do we look at hardware. Also read repairing or buying a new MacBook.