When your Mac stuck on loading/login screen, there is nothing much you can do with the operating system to diagnose and fix the problem. But it is not the end of the world, you still have great chances to fix the issue without the help of technicians. Just follow this guide to bring your Mac computer back to life.
Solution 1: Check your power connection.
The first guess should be your Mac computer is run out of battery. Ensure that your Mac is plugged in correctly and the power is on. Secondly, it may be the fault of the power cable or adapter. You can find a power cable or an adapter that fits your machine and try it to see if that fix the problem. If not, you can try the following solutions.
Solution 2: Check the display
If you are using desktop on Mac, it could be a problem with your display. Press the Caps Lock to see if it lights on. If it glows, then your display is probably off. Please check all its cable are connected seated and disconnect all peripherals if necessary.
Solution 3: Perform the special power cycle
After the above checks, if your Mac still won't start normally, you can try to reboot your Mac in a special mode, named "special power cycle".
1. Unplug the power cable.
2. Hold down the Power button for about 10 seconds.
3. Without releasing the Power button connect the power cable.
4. Wait 10 more seconds holding it.
5. Let go of a button and start your Mac in a normal way.
Solution 4: Try Recovery Mode
Assuming your Mac is booting up but the operating system isn't loading properly, the system drive may be corrupted. Fortunately, if you boot into Recovery Mode, it's possible to restore lost files from Time Machine, repair the corrupted Mac's disk in Disk Utility or reinstall the macOS.
How to enter the Recovery Mode?
To access the Recovery Mode, make sure your Mac is off. If the Mac stuck on white or grey screen, just hold down the Mac's power button for several seconds until it gives up. Then restart your Mac and immediately press and hold Command + R when you hear the Mac's startup sound. Don't release the keys until you see Apple logo.
Restore files from Time Machine
1. In the macOS Utilities windows, click Time Machine.
2. From Time Machine window, select the image file that needs to be restored.
3. Once the file is selected, then click on Restore.
Use Disk Utility in Recovery Mode
1. Press and hold the Command and R keys while tapping the power button to start your computer.
2. From the macOS Utilities menu, select Disk Utility.
3. Select the startup disk or partition.
4. Click on First Aid on the top. Wait until the fixing process finished.
5. Click Done and restart your Mac.
Reinstall the macOS
If Disk Utility can't repair the disk, you need to reinstall the macOS. The reinstallation process will erase all data on the Mac computer, so please back up firstly. If unfortunately, you didn't back up with Time Machine or Time Machine failed to update backups. You can use iBoysoft Mac Data Recovery to recover lost data from unbootable Mac computer.
Step 1: Data Recovery from unbootable Mac computer
iBoysoft Mac Data Recovery is a free Mac data recovery software that is able to recover Time Machine backups, recover data from failed internal Mac hard drive, recover data from unmountable APFS boot volume, as well as from unmountable Macintosh HD, unreadable, inaccessible APFS external hard drives, USB drives, SD cards, Pen drives and much more. It is compatible with macOS Mojave/High Sierra/Sierra and OS X.
Method 1: If you have only one unbootable Mac computer
If you have only one Mac computer, please directly run iBoysoft Mac Data Recovery bootable media from iBoysoft Server and recover lost data from the unbootable Mac computer.
Method 2: If you have two Mac computers
1. Download iBoysoft Mac Data Recovery on another Mac computer.
2. Install and launch iBoysoft Mac Data Recovery.
3. Click iBoysoft Data Recovery on menu bar and then select "Create Boot Drive".
4. Insert a USB drive into your Mac computer.
5. Follow the wizard to create a bootable recovery drive.
6. After that, please insert iBoysoft Mac Data Recovery bootable USB drive into the unbootable Mac computer, and then press the Power button and Option key (⌥) to start the computer up.
7. Select iBoysoft Mac Data Recovery from the boot options.
8. Follow the wizard to scan for lost data on the unbootable Mac computer.
Step 2: Erase the startup disk in Recovery Mode.
1. Boot your Mac to Recovery Mode.
2. Select Disk Utility from the macOS Utilities menu.
3. Select the startup disk from the side bar.
4. Click on Erase from the top.
5. Setup the required information to reformat the disk and click Done when finished.
6. Go back to macOS Utilities screen and select Reinstall macOS.
Solution 5: Boot up your Mac in Safe Boot
Safe Mode checks through your startup drive to make sure there are no problems there. It helps you resolve problems that are stopping your Mac from starting up. To boot up your Mac in Safe Mode, begin with your Mac switched off or restart it. Press and hold the Shift key. Then release the Shift key as soon as the login window appears. If you have FileVault turned on, you need to log in twice.
Solution 6: Reset the PRAM / NVRAM
NVRAM or PRAM stores the information about system settings, including system date and time, screen resolution, etc. If it get corrupted, you Mac won't boot as usual.
1. Press the Power (Eject) button.
2. Immediately press and hold down the Option (Alt) + Command + R + P keys together for 20 seconds (or until the screen goes all black and comes back to gray again, or you hear the startup sound (in some old models).
3. Release the keys simultaneously.
4. Wait while your Mac boots.
5. Get to System Preferences and re-configure the settings as needed.
Solution 7: Reset System Management Controller (SMC)
If none of these steps resolve the problem, resetting SMC is the last thing you should try. System Management Controller (SMC) is responsible for the power-operated components such as CPU fan, LEDs, etc. Resetting SMC can help to erase any corrupt information, and set the configurations by default.
On a MacBook Pro without Removable Battery
1. Shut down Mac and plug in the power cord.
2. Press Shift-Control-Option, then press Power button.
3. Hold the keys for about 10 seconds.
4. Release the keys.
5. Press Power as you would normally start your Mac.
On MacBook Pro with Removable Battery
1. Unplug your MacBook Pro from the power supply.
2. Remove its battery.
3. Press and hold down the Power button for 5 seconds.
4. Release the Power button.
5. Place the battery back in.
6. Re-connect to the power supply.
7. Press the Power button to boot your MacBook Pro.
On a desktop Mac or Mac Pro
1. Unplug the power cable.
2. Give it 15 seconds.
3. Plug the cable back in.
4. Wait 5 more seconds and press Power again.