Mac Safe Mode: What Is It And When To Use It

Safe Mode is a way to reboot your Mac that can help you diagnose problems, and sometimes even fix them without doing anything more. Learn how to boot into Safe Mode and steps you can take to fix your Mac.
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Video Transcript: Hi, this is Gary with MacMost.com. Today let me show you how to use Safe Mode on your Mac.
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So Safe Mode is a different way to boot up your Mac. It's a tool that you can use if your Mac is having trouble to both diagnose what the problem may be and also possibly fix it. So when should you use Safe Mode. Well, only if you're having trouble. I know a lot of people are going to be tempted to just try Safe Mode to see whether or not your Mac gets a little faster or more efficient or something like that. But it's really only there if you're actually having trouble. Like for instance your Mac won't boot at all. Or you're getting constant errors and app crashes. Or perhaps your Mac is really slow and freezes up for long periods of time or other like really severe problems. Things that you weren't having a short while ago and now suddenly your Mac isn't working right. Safe Mode is one thing you can use to try to fix this. Now it may not solve the problem. The issue may not be something that Safe Mode addresses. But it's worth a try. 
So what does Safe Mode do? Well, it does a few things. First while booting up in Safe Mode it's going to run some system checks. It's going to do something very similar to Disk First Aid. That's when you boot into recovery mode, run disk utility and run First Aid to diagnose and fix problems on the drive. It's going to do something similar to that. So if there's a disk issue booting into Safe Mode may not only find the problem but may fix it. It's also going to boot without using system extensions particularly ones installed by third party apps. So if you have an app installed, something that's adding something to the system and that's causing a problem then booting into Safe Mode won't be using that extension and then you could see whether or not the problems still exists when you're in Safe Mode. It's also going to not install anything but the basic system fonts. So if there is a font causing the issue then going into Safe Mode could reveal that. It's also going to clear out certain caches. Caches are bits of data stored on your Mac to help speed things up. Things like the Kernel Cache, which is the core of your Mac operating system, and also the Font Cache are cleared out when you boot into Safe Mode. So if the problem is caused by those booting into Safe Mode would actually fix the problem. So let's talk about how to boot into Safe Mode.
There are two different methods depending upon which Mac you've got. If you have an older Intel Mac then it's pretty simple. All you need to do is shut down your Mac and wait for ten seconds. Then when you boot up your Mac again, while you're pressing the power button, also hold down the Shift Key. Keep the Shift Key held down until you see the login screen. Then you're in Safe Mode. Now if you have a new Mac, one that's using the Apple silicone chips like the M1 chip, then you do it differently. You still shut down and wait ten seconds. But now you boot up by holding the Power button and you continue to hold the Power button. You don't need to use the Shift Key at this point. Then it will show you a message telling you to continue to hold down the Power button for more options. Then you'll see a message saying it's booting with more options. At that point you can remove your finger from the Power button. Let it finish booting. Now to get to Safe Mode first select the Startup Disk. You probably just have one internal drive as your Startup Disk. Then hold the Shift key down and the little bit of text underneath it will change to indicate that you could boot into Safe Mode. Click that. Now just wait for your Mac to finish booting. Now it could take awhile because it's going to run all those disk checks, clear those caches, and do a bunch of things. So be prepared to wait. Go grab a cup of coffee or go to lunch and let it finish booting into Safe Mode. When it's done you'll see in the login screen a little red indicator at the top right saying you're in Safe Mode. Then once you're logged in your logged in now in Safe Mode. 
Okay that's how to do it. But how do you actually use Safe Mode to fix problems on your Mac. Well, first is when you have an issue you should try some things before Safe Mode. Try a regular reboot to see if that fixes the problem. Then if you're using a lot of apps at the same time after your regular reboot don't launch any new apps at all. Just launch, maybe, the one app you need to use and see if you're having trouble there. Then try to notice when trouble starts and which app it was that you added to the mix. In that case you know the trouble with that app has nothing to do with Safe Mode and you need to contact Support for that particular app. If you do try Safe Mode to try to fix things then after you've booted into Safe Mode what you want to do is test to see if the problem is still there. You don't want to use your Mac for too much. Remember you're now without some system extensions. You're now without some fonts. So you don't want to actually do any serious work. But test things out. If everything seems to be working fine now then maybe Safe Mode fixed the issue. In that case reboot and go back into normal mode so you can get back to work. If at that point if everything seems fixed then you know that one of the things that Safe Mode did actually fixed the problem. 
However, if you notice the problem returns after booting normally then you know that it's probably some sort of system extension or a bad font or something that's causing the issue. After all it works fine in Safe Mode but not in regular boot mode. So then you need to go and do other things besides Safe Mode to fix the issue. Make sure all the old software you have is up-to-date. It could be an old version of an app you're using has a bug in it that's fixed by a newer version. See if there's some software you have that you no longer need and disable or uninstall it. If you have anything that runs in the background, anything like a cleaner app or anti-malware or something like that it's always running and doing something behind the scenes, try disabling that. Not using it for a little while and see if that was causing the issue. Also consider any hardware accessories you have attached. Anything that you have attached by USB or Thunderbolt could also be contributing to the issue. Try disconnecting them. See if the problem is still around after you reboot with those detached. If the problem only exists when you attach these items you know that that item is causing the issue. 
Another thing that you could do is to create a new user account on your Mac. You can create as many user accounts as you want. So create a brand new user account and see if the same problem happens to that user account. You don't need to use that user account for anything other than just testing. But if the problem isn't happening when you log into that user account but it is happening when you log into your regular user account you know something that is being launched in that regular user account is causing the issue. You can go into System Preferences, Users & Groups, and check Login items to see what's there. Although not everything appears there. A lot of software that you install won't be listed here but still launches something whenever you login as that user. So again go through the software you have installed to see what you can disable or uninstall temporarily and check to see if that fixes the problem.
Now if all that fails then Safe Mode didn't work and any of these other techniques didn't work then you probably would want to make an appointment at the Genius Bar or with a Mac expert to have them take a first hand look at your Mac. Now if you want more information about Safe Mode, Apple has this page that you can checkout. So go there to read more about it. Hope this helps. Thanks for watching.
Mac Safe Mode: What Is It And When To Use It

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