10 Solutions: Mac Won't Turn On After Update to macOS Big Sur or Catalina

Connie Wisley
time November 13, 2020 Preview 2.7K
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The public version of macOS 11 Big Sur has been released on Nov 12th, many of us may have downloaded and installed the new version, and feel extremely excited about its new features. While, some of us are suffering from upgrading to macOS Big Sur for different reasons, such as Mac won’t turn on after update to macOS 11. If you run into such a problem, you can find the most complete guide ever to get it solved, also you are given the best solution to deal with lost data after such an undate.

10 Solutions: Mac Won't Turn On After Update to Big Sur or Catalina

The “Mac Won't Turn On After Update” issue can be caused by different reasons, here we collect 10 feasible solutions to get it fixed.

#1 Restart

Whenever a problem occurs, restarting your device is always the simplest yet efficient way to fix it. Restarting can start up the mac fresh by clearing memory. And there are 2 ways to restart.

Method 1

Leave the Mac as it was, press and hold on the Power button to turn the mac off, then hold and press the Power button after several seconds to turn the mac ON again, also you can press the hot keys combination to restart your mac: Control+Command+Eject.

Method 2

Disconnect all the accessories on your mac, particularly the recently installed memory or hard disk that may be not compatible on your mac. Then press and hold the Power button to turn the mac off, then press and hold the Power button again after seconds to turn on the mac. Also, you can press Control+Command+Eject on your keyboard to restart the mac.

#2 Check the Display

It seems to many mac users that there is no necessity to check the display when a mac won't start after update to Big Sur or Catalina. But, it is not. Sometimes, it is just the reason of a damaged or unconnected display. When you start the mac, listen carefully if it makes any sounds, if yes, Display won’t be the problem, if not, re-connect the power cables, then restart. If it still fails to turn on, find a technician.

#3 Check the Power

Power is required to turn on a mac and we need to make sure there is enough power supply to run a mac.

If you are using Mac with battery, make sure there is enough power for macOS update, the upgrading takes time. Or you can remove the battery and plug in a charger to make sure there is enough power supply.

If you are using mac connecting to power supply, make sure the power cord and adapter are plugged in properly. If it still doesn’t work, unplug and re-plug to check and test, or you can test with a lamp or other device.

#4 Use Apple Diagnostics to Check Hardware Problems

There will be some hardware-related reasons causing the “Mac won't turn on after macOS update”, in this case, you can use Apple Diagnostics to find out the problem.

Apple Diagnostics helps to test mac hardware and suggests solutions, that is to say, you can use this tool to find out which hardware on your mac runs into a problems.

  1. Remove all external devices;
  2. Press Power button to restart;
  3. Press and hold D key when mac restarting;
  4. Apple Diagnostics will start automatically, once finishes, follow its suggestions to fix hardware issues;apple diagnostics

#5 Run Disk Utility/Terminal in Recovery Mode

As we mentioned above, a damaged hard drive or SSD may be the reason stopping your from open the Mac after update. Besides using Apple Diagnostics, users can also use Disk Utility in Recovery Mode to repair the disks for mac start-up.

  1. Press Power button;
  2. Press and hold Command+R;
  3. Release Command+R when apple logo appears on the mac screen;
  4. Choose Disk Utility in the macOS Utility interface;disk utility
  5. Select the drive and choose First Aid to repair your disk. Also, you can try Terminal to do the repairing.

#6 Boot Mac in Safe Mode

If your mac won't turn on after update to macOS Big Sur or Catalina, you can try to boot mac in safe mode. Mac safe mode is a way to start the mac while performing some checks and repairing your mac, also preventing some programs from launching automatically, which is a good way to build an efficient environment to start your mac.

  1. Press the Power button to start your mac;
  2. Press and hold Shift key when you hear the start-up sound;
  3. Once you see the Apple logo, release the Shift key and wait for your mac to start in safe mode;boot mac in safe mode

#7 Reset NVRAM

NVRAM means non-volatile random access memory, it refers to a small amount of special memory in each mac to store the information that your mac needed before it loaded the operating system. If there is something wrong goes on the values of NRRAM, your mac won’t start up, and this happens when you upgrade your mac to a new macOS version. So, we can reset NVRAM if your mac doesn’t turn one.

  1. Press Power button, then press and hold Option+Command+P+R for 20 seconds;
  2. Then release the keys to allow your mac to continue starting;
  3. Then check the Startup Disk, Display, Date & Time and reset as needed.

#8 Reinstall macOS

Sometimes, a problem just appears during the 1st installation of a new macOS version and reinstalling can magically solve the problem.

  1. Press Power button;
  2. Once you hear the sound, press and hold Command+R;
  3. In the macOS utilities interface, choose Reinstall macOS;reinstall macos catalina
  4. Pass the option to format disk and follow the onscreen guide to complete the installation.

#9 Reset SMC

SMC means System Management Controller, a component of your mac hardware storing settings about power management, temperature monitoring, keyboard backlights and others. Though Apple doesn’t suggest resetting SMC without trying other possible solutions to fix the “Mac Won't Turn On After Update”, it neither mentions any adverse impact by trying this method. If you have tried all possible solutions but still fail, you can reset SMC.

Methods to reset SMC on different mac will vary a little:

For Desktop Mac---Disconnect the power cord and wait for 15 seconds, then connect it back and wait for 5 seconds, finally start the mac.

For Portable Mac with removable battery---Shut down the mac, disconnect the power cord and take out the battery. Now, press and hold Power button for 5 seconds. Then put the battery back, connect the power cord and turn the mac on.

#10 Contact Apple Support

Well, if you have tried all above-mentioned solutions but mac still doesn’t turn on, you’d better contact Apple.

1) Turn to Apple Support Page and contact

2) Visit an Apple Store

3) Find authorized service provider.

If it is not that convenient for you to contact Apple Support locally, you can pay to a reliable local technician to fix such a problem.

Small Tips to Avoid “Mac Won’t Turn On After Big Sur or Catalina Update”

In fact, if you get your mac well-prepared well upgrading to Big Sur or Catalina, it will be much likely that the new macOS can work properly on your mac. For further macOS update or speedy OS running, you can try following tips:

  1. Remove unnecessary extensions. Extension can easily alter your settings;
  2. Disable unnecessary, especially antivirus apps from auto running when updating;
  3. Clean your mac regularly, especially the Trash bin to save space as much as possible;
  4. Run Terminal to scan and repair your hard drive when your mac runs slowly or work improperly;

What if Data Lost after Update to macOS 11 Big Sur or Catalina?

Data loss is always the most annoying problem after upgrading to macOS Big Sur or other new versions. Some your files just disappear for no reason. To help your recover the lost data during updating, here we recommend Cisdem Data Recovery for Mac.

Cisdem Data Recovery is designed to recover virtually all kinds of data lost due to system update, factory resetting, deletion, formatting, virus attack, etc., no matter you want to recover files from external or internal hard drive on mac.

Step 1Download and install Cisdem Data Recovery on Mac.

Free Download

Step 2Choose a recovery mode.

You can choose the Basic Data Recovery mode for your 1st scanning, if you are not satisfied with the recovery result, go to advanced recovery mode.

cisdem data recovery for catalina

Step 3Select the hard drive and click "Scan" for scanning

cisdem data recovery for catalina

Step 4Preview found files before recovery

Once the scanning finishes, all the found files will be filed in different folders, find the ones you want to recover and preview.

cisdem data recovery for catalina

Step 5Recover lost file after updating to Big Sur or Catalina

Select all the files you want to get back, then click “Recover” to restore the lost files onto your mac.

Conclusion

When Mac won't start after update to macOS Big Sur or Catalina, you need to restart first. If still fails, try above-listed methods to fix it. In addition, there is one thing you should pay attention to before upgrading macOS, back up all important files. Even if you lost files during the update, you can still restore them without using a piece of mac data recovery software.

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Connie Wisley
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Connie has been writing for Mac productivity and utility apps since 2009. Each review and solution is based on her practical tests, she is aways energetic and trustworthy in this field.

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