How to fix a Mac that wont start ?.


Before we begin, we are obliged to ask you two questions. Have you tried restarting your computer ? Have you checked that it was plugged in ?

If this is the case, please read on !

Verify that your Mac turns on.


“Turn on” and “start” are two terms often used interchangeably. Here, “light” refers to the fact that the computer has been started and “start” refers to the launch of the operating system.

To verify that your Mac turns on, press the start button of your computer and listen with attention. If the fan goes off, it is that your Mac is able to turn on (even if nothing appears on the screen). If there is no noise, no reaction, do the following two actions.

Use another charger or power supply cable : it is possible that your Mac does not turn on because the power cable does not work any more.

Disconnect the accessories : some printers and external hard drive (among others) can interfere with your computer.

If nothing happens, go directly to step 8.

Force it to restart.


When your Mac is on, but does not seem to give no sign of life, force it to restart. For this, nothing more simple, you just need to press and hold the power button for 10 seconds. You should hear a “click” which confirms that the power has been turned off. Wait at least 10 seconds before you turn on your computer.

Look at the screen.


If you are using a iMac, the problem may be the screen and not the computer itself.

Apple has published a guide of the different problems that can occur with the display of your screen.

The recovery mode.


If your Mac starts but the operating system does not start, this may be due to a damaged disk.

To resolve this problem, run the disk utilities :

– Force shut down your computer by unplugging it or by holding its start button pressed.

– Press the keys Command and R and hold the press) by restarting your computer.

– Your Mac is in recovery mode, which gives you access to disk utility.

– Click on the icon of your hard drive called disk Utility then click Verify disk. If errors are detected, a message will appear asking if you want to restore.

The recovery mode also gives you access to your Time Machine and allows you to reset your Mac and look for help online via Safari.

The mode without failure.


The safe mode allows to start a Mac in spite of its bugs, and in view of the repair.

– Turn off your Mac.

– Turn it on again by holding the keys Shift, Command and V supported.

Check the file system.


– Turn off your Mac and turn it back on by holding down the keys Command and S.

– You can release the keys when the black screen (with messages written in white) is displayed.

– Wait until the text has finished displaying, then type fsck-fy and press Return. Wait a few (long) minutes.

One of these messages will eventually be displayed, either “The volume -the name of your mac appears to be OK” or “FILE SYSTEM WAS MODIFIED”.

If you find yourself opposite to the first message, type reboot and press Return.

If you find yourself facing the second message, retype the command fsck-fy and press Return. If you get the same result, go to the next step.

Reset the NVRAM.


The NVRAM stores data which do not disappear even when the computer is turned off (sound volume, screen resolution, etc).

Reset these data can be useful sometimes, and it can’t do harm to your computer.

– Press and hold Command, Option, P and R while restarting your computer. When you hear that the computer to restart once, release the keys.

In some cases, resetting the NVRAM will allow your computer to restart normally. However, it may be that your computer doesn’t manage to complete this order (the progress bar stops along the way).

To reset the SMC.

One of the last steps before you reinstall your macOS is reset the system’s management controller (SMC).

On a portable computer, press Shift, Control and Option/Alt at the same time as you plug in your charger.

For a fixed computer, unplug 15 seconds, and then plug it back in. Wait 5 seconds before turning it back on.

Use the target disk mode.


This step should be done before you reinstall your OS X and depends on your backup mode.

If you have already backed up the contents of your computer through your Time Machine, a Cloud or an external hard drive, you can directly skip to step 10. If not, try saving the data as you can, and for this you will need to borrow to someone with a different Mac.

– Connect the two Macs using an Apple Thunderbolt cable, FireWire (depending on the model of your computer).

– Turn off your Mac (force your computer to shut down if necessary).

– Turn on your computer holding the T key pressed.

– Hold down the T key pressed until the icon of Thunderbolt displays on the screen.

Your computer is now in target disk mode, which means that it acts like an external hard drive. Normally you should see it appear in the Finder on the second Mac. You can import the files you want to the second Mac, or even clone your entire hard disk and save it on an external hard drive.

Reinstall Mac OS X.


You can reset your Mac OS X, MacOS Sierra (and soon MacOS Majave) from the disk utilities.

– Force shut down your computer by unplugging it or by holding its start button pressed.

– Press the keys Command and R and hold the press) by restarting your computer.

– Your Mac is in recovery mode, which gives you access to disk utility.

– Click on Reset MacOS.

For more details on this step, we recommend that you read the tutorial from Apple.

Make an appointment at the Genius Bar.


If you’ve tried the various tutorials above, but your computer refuses to turn on, it is time to make an appointment at the Genius Bar !