How to speed up a Mac

Each step below is free, and each is worth trying in this order: the early ones take a minute and fix the most. If you are not sure why the Mac is slow in the first place, spend a minute on finding the cause first.

1. Restart

A Mac that has been up for weeks carries stuck processes, leaked memory and a swap file that has only grown. A restart clears all three and empties macOS's temporary folder safely. Apple menu → Restart, and leave "Reopen windows" unticked once to see the Mac clean.

2. Install updates

System Settings → General → Software Update. macOS updates fix performance bugs as well as security ones, and app updates do the same for the apps you use most. Browsers especially.

3. Close what holds the memory

Open Activity Monitor, go to the Memory tab and sort by Memory. The top of that list is what to close. A browser with dozens of tabs is usually first: close the tabs you are not using rather than the whole browser. When the Memory Pressure graph at the bottom drops back to green, the Mac stops swapping and the stutter goes.

4. Trim what opens at login

System Settings → General → Login Items & Extensions. Remove the apps you do not need the moment you log in, then look at "Allow in the Background", where updaters and helpers run without a window. Turning one off there stops it starting on its own; it does not uninstall the app. If the helper belongs to an app you no longer use, uninstall the app and the helper goes with it.

5. Keep free disk space

macOS needs room on the startup disk for swap, caches and updates. A Mac with only a few gigabytes free swaps slowly and cannot install the update that might have fixed it. How much to keep depends on the Mac, but a macOS upgrade alone wants tens of gigabytes, so treat single figures as urgent. How to free up space covers every place worth checking, and if Storage settings blames System Data, see what System Data is on a Mac.

6. Reduce visual effects on an older Mac

System Settings → Accessibility → Display: turn on Reduce motion and Reduce transparency. On a recent Mac you will not notice the difference; on an older Intel Mac with a busy display it takes work off the graphics chip.

7. Rebuild Spotlight if search has stopped working

If Spotlight is slow or finds nothing long after an update, the index is damaged. Rebuilding it takes a while, and the Mac is busy while it runs, so do it at the end of the day. It is one of the maintenance jobs RefreshYourMac measures before offering.

The fixes that only look like fixes

• "Free up RAM" buttons empty a cache macOS drops by itself whenever an app needs the room. The Mac reads it back and is briefly slower. The measurement is on does purging RAM help.
• Clearing every cache frees space, but apps open more slowly until they rebuild it. Worth it for space; not a speed boost.
• Repairing disk permissions has had nothing to do since OS X El Capitan.
• Running the maintenance scripts: macOS no longer ships the periodic command they ran.

When it is the hardware

If memory pressure is yellow or red with only one or two apps open, the Mac does not have enough memory for what you ask of it, and no software changes that. The same goes for an older Mac running the newest macOS. Knowing that is worth something too: it stops you paying for a tool that promises otherwise.

Where the app comes in

RefreshYourMac handles steps 3 and 5. Its menu bar window shows memory pressure and the swap rate, and lists the apps actually holding memory with a button to quit one. Its scan measures 45 categories of disk space, rates each one with a safety level, and can clear the safe ones on a schedule so the disk does not fill up again.