Find out what is slowing down your Apple Mac and how to fix it

Find out what is causing the Apple Mac to slow down, such as auto-starting processes.

If your Mac suddenly starts slowing down, what is the cause and how do you fix it? There are several possible causes and you must do some detective work using built in and third party tools.

Old Macs suffer more problems slowing them down than new models and if your Mac is really old and has a hard disk drive, it is even worse. New Macs have more memory and solid state drives, but even so, problems can occur.

I like to use Chrome for web browsing because it is the best for cross-platform work. It runs on everything - Mac, PC, iOS and Android - so my bookmarks, browsing history and extensions follow me wherever I go. Unfortunately, Chrome is one of the main reasons my Mac runs slowly.

Any app can cause problems of course, and I have tracked down the ones on my Mac that cause problems. Have you tracked down the cause on your Mac? How do you go about it?

Check CPU usage with Activity Monitor

Activity Monitor is a very useful app for looking at the apps and processes that are running in the background. Find it clicking Go > Utilities and then run it.

There is a list of processes, but not all of them may be displayed. Go to the View menu and select All Processes.

Select the View tab and then click the CPU column header. The processes are sorted with the ones using the CPU the most at the top (click the CPU column header again to reverse the sort order if the least CPU usage is at the top).

Check the CPU usage in Activity Monitor on the Apple Mac

The items at the top of the list are the ones using the most CPU. Here you can see that Google Chrome Helper is using 150% CPU. Two more Google Chrome processes a little way down the list add another 46% CPU. That is nearly 200% CPU in total!

No wonder the Mac was extremely slow and unresponsive, it is working flat out!

Macs slow down when one app uses too much CPU. Find out which app it is and close it.

Check memory usage with Activity Monitor

Select the Memory tab and click the Memory column header to sort the processes by the amount of memory they are using (click again to reverse the sort order). Here you can see that Google Chrome is using nearly 3GB of memory and this particular Mac has just 4GB of memory installed.

Check app memory usage with Activity Monitor on the Apple Mac

Chrome does this sometimes and often the problem is a single tab. Either there is a fault with the web page or with Chrome’s handling of it and it has a runaway memory usage problem. It consumes memory and CPU like crazy.

This is not just a Chrome problem and sometimes other apps do a similar thing and drive the memory usage up to the max. If memory is limited, such as with 4GB and 8GB systems, too much memory usage slows down the Mac. Macs with fast SSDs are better able to cope with a memory shortage, but old Macs with hard disk drives suffer terribly. Activity Monitor can be used to see which app is causing the problem.

The solution is to shut down that app causing the problem. Restart it afterwards and everything is back to normal. Don’t do whatever caused the problem. In the case of Chrome, avoid that bad web page.

Use KnockKnock to see what is auto-loading

KnockKnock is a free app that digs deep into the operating system to discover what is loading when the Mac is started.

Every extra item that loads will slow down the startup and it takes longer to get to the desktop and for you to start working. Startup items may run in the background using processing power and memory, which adds to the Mac’s workload, which causes it to run more slowly than it otherwise would.

Extra startup items is one of the reasons an old Mac runs more slowly than it did when it was new.

Run KnockKnock and click the big button at the top - Start Scan. All the items that start with macOS are organised into categories on the left. Select a category to see a list of the items.

KnockKnock for Apple Mac checks for startup items

An (i) icon on the right opens a small window with information about the file and the eye icon opens a Finder window to show the file. The app simply shows lists the auto-starting items and it does not do anything to stop them. It is purely for information purposes and it is up to you what you do.

Sometimes the solution is to uninstall the software responsible if it is no longer needed. Sometimes an app has been uninstalled, but not everything was removed and you may need to delete the remaining files manually.

The app does not give any advice on what to remove or how to remove it and you may need to Google items that are found to see what they are and if they are safe to delete.

KnockKnock is able to detect malware and it sends suspicious items to VirusTotal. This is an online service that scans files for malware and reports if they are clean or not. Sometimes malware is responsible for the Mac running slowly.

Check for Mac malware with KnockKnock

Some technical knowledge is required with KnockKnock, but it is still a useful tool.



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