Sudden and Frequent Restarts

Sudden and frequent restarts, particularly those accompanied by an onscreen warning, are known as kernel panics. This is the Apple equivalent of Microsoft’s Blue Screen of Death, and you often see the “Your computer was restarted because of a problem” error when your machine reboots.

Many things can cause a kernel panic. It could indicate a problem with hardware, such as RAM or CPU. An unreliable peripheral you have connected to your Mac can also cause a kernel panic, or it could simply be a case of low disk space. Kernel panics happen occasionally, but if you aren’t experiencing them frequently (multiple times per week), you shouldn’t worry too much about it.

If your Mac has regular kernel panics, try these possible fixes:

Remove any peripherals that might be causing the issue.  For example, if the panics only happen when your webcam is plugged in, run your machine without it for a week, and see how things go. Check whether you have enough free space.  If you need more space, you can delete files to create more. Run memtest86 to test your Mac’s memory.  You’ll need to create a bootable USB flash drive and test your computer’s memory outside the macOS environment. If you find any issues with RAM, you can try replacing it where possible. Run Apple Diagnostics.  To do this, press and hold the D key while you boot your Mac, and then see if any hardware issues are detected. Boot into Safe Mode.  Press and hold the Shift key while your system starts to boot into Safe Mode. See if the problem persists. Safe Mode excludes any third-party kernel extensions, which could be causing the issue. It will also scan your volume for errors and fix anything it finds. Reinstall macOS from scratch. This is the nuclear option, but it will likely clear any software that’s causing the issue.

Freezes and App Crashes

Do you regularly see the spinning pinwheel of death? Are apps unresponsive, sluggish, or crashing altogether? Does your Mac suddenly freeze for no reason?

Many things could cause these issues, but some are more common than others. Low disk space often causes performance issues, particularly when you wake your Mac from Sleep Mode. Issues with memory and storage, or simply a machine that bites off more than it can chew, could also be to blame.

If you’re experiencing these issues, try these possible fixes:

Create more disk space.  You might just need to give macOS some room to breathe. Try to keep around 10 GB of free space on your drive for macOS housekeeping duties. You can delete and move files to free up more space on your Mac. Run memtest86 to check your Mac’s memory for issues. You can also press and hold the D key while your Mac boots to run Apple Diagnostics and scan for other hardware issues. Run Disk Utility. If your machine has a hard drive, launch Disk Utility, select the drive, and then click “Verify Disk. ” If you see any errors, click “Repair Disk. ” This can isolate bad sectors, so macOS knows not to store data in those sections of the drive (a common cause for the pinwheel of death). Reinstall macOS.  This will remove any software-related issues and free up a ton of space. Your Mac should then perform at the fastest speeds it can manage. Delete resource-intensive apps.  If you suspect the issues are caused by aging hardware, ditch apps like Chrome for lighter-weight options, like Safari. Try using SimpleNote and GIMP instead of Evernote and Photoshop.

Declining Battery Life

Batteries don’t last forever. Over time, they all exhibit signs of aging. For example, your device won’t run as long on a single charge, and, sometimes, it will barely hold a charge at all. There’s one very clear course of action in this case, but it’s not the only thing you can try.

Power issues can also point to problems with the System Management Controller (SMC). This chip in Intel-based Macs is responsible for low-level operations, including charging LED behavior and fan control.

If you’ve noticed battery issues, try these possible fixes:

Check the health of the battery. The most common cause of poor battery life is that it’s in poor condition. Fortunately, macOS can tell you exactly what condition your battery is in, how many charge and discharge cycles it’s gone through, and whether it’s time to replace it. Reset the System Management Controller (SMC). If the battery’s in good condition, resetting the SMC might resolve some power-related issues, like a Mac that won’t charge. Extend your Mac’s battery.  This is a good idea if you regularly use your Mac for long periods without a main power source. Adjust your habits when you use battery power. Start Activity Monitor and click the “Energy” tab to see which apps use your battery. Perform tasks like video and photo editing only when your Mac is plugged into a power source. Use Safari for web browsing—it’s much more efficient than Chrome or Firefox.

Your Mac Won’t Boot

Many of us panic when our computers don’t boot correctly. You might see a plain black or gray screen, a black screen with a question mark, or an error message about an issue your machine is having.

Like system crashes, there are many reasons why a Mac might appear to be DOA. It could be an issue with a cable, the SMC, a software update, or a botched OS upgrade.

If your Mac isn’t booting properly, try these possible fixes:

Check the cables.  Make sure everything is plugged in and that the socket is switched on at the wall (if applicable). It’s always worth it to check this first. Boot into Safe Mode.  To do this, press and hold the Shift key while your Mac boots. Safe Mode will verify your disk, and then start your machine with the bare minimum it needs to function. You can then try to restart normally. Run through our checklist.  We’ve covered this particular problem in-depth before. If the basic troubleshooting steps in this article don’t work, move on to others you can try. Reinstall macOS. When all else fails, you can boot into Recovery Mode and reinstall the OS from scratch.

Erratic Fans, Strange LED Behavior, and Power Issues

This worked for me:

Shutdown.Hold Power 10 seconds. (Let’s add don’t breathe).Let go. (You can breathe now). Press power again quickly.

Fan speed back to normal.

— Todd Bruss (@StarPlayrX) November 12, 2019

The System Management Controller (SMC) is responsible for low-level operations that can’t necessarily rely on the main operating system. These operations occur before the OS even boots, and, on Intel-based Macs, the SMC chip controls them.

If the SMC has a problem, you might encounter fans that constantly run, battery and indicator LEDs that misbehave, or keyboard backlights that don’t respond to controls. You might also experience power issues, like sudden shutdowns and a refusal to power on.

The SMC can also cause issues with battery charging, external peripherals not being detected, and poor performance, even under a low CPU load. These issues are mostly just irritating, but some can seriously impact how you use your machine.

Fortunately, the fix for this relatively straight-forward; just follow these instructions to reset your Mac’s SMC.

Your Mac Forgets Settings

When your Mac is shut down, many settings, like the current resolution, which startup disk the machine uses, your local time zone, and the volume are all stored in the Nonvolatile Random Access Memory (NVRAM) or Parameter RAM (PRAM).

Occasionally, things go wrong, and these settings are lost. Your Mac might boot from a different startup disk than normal, or you might constantly have to reset the time and resolution after the system boots.

To fix these issues, you need to reset the NVRAM/PRAM on your Mac.

Your Mac Is Overheating

If your Mac is overheating, it’s pretty obvious because it will feel hot. Further signs include thermal throttling (when macOS limits the speed of your CPU to generate less heat) and random restarts. To check the internal temperature, you can install an app like smcFanControl.

Aside from using your Mac in very hot conditions, overheating might signal a more serious problem you shouldn’t ignore. If there’s a problem with the internal cooling or temperature sensors, and you continue to use your Mac, you could damage it. Hardware and heat don’t mix.

If your Mac is overheating, try these possible fixes:

Reset the SMC.  Because it controls the fans, this could potentially solve your problem. Take it in for repairs. If you don’t hear any fan noise, it’s possible there’s a problem with the cooling system or temperature sensor in your Mac. If this is the case, take your computer to a technician, as continued use could damage your machine.

Your Mac Doesn’t Shut Down Properly

A Mac that won’t shut down is not as common or panic-inducing as one that won’t boot. However, if this happens frequently, it’s likely third-party software is running in the background and blocking the shutdown procedure.

If your Mac doesn’t shut down, try these possible fixes:

Quit any open apps. You might need to force quit some apps that have crashed. You might also want to use Activity Monitor to check for processes that aren’t responding. After you close everything, try to shut down your Mac again. Unplug any peripherals.  Remember to safely eject any external drives before you unplug them. Force your Mac to shut down. Press and hold the Power button (or the Touch ID fingerprint reader) until the screen goes black. Try the suggestions on our checklist.  If the suggestions above don’t fix the problem, try the troubleshooting steps outlined in our previous article on this topic.

Get Help From Apple

Even if your Mac is outside of its warranty period and not covered by AppleCare, you can still take your Mac to Apple store and get some help. A technician can run model-specific diagnostics on your device to detect any hardware issues. Outside of downloading leaked copies of these diagnostic tools, there’s not much else you can do.

Apple will let you know if any repairs need to be done, and you can decide if it’s worth it. Depending on the cost, it might be better to upgrade to a new model. Apple won’t charge you anything unless you agree to the repair or hardware replacement.