There are many reasons for that Macbook OS X won’t boot up all sudden. It might be power source, software issues,hardware issues, update issues, and etc. However we are going to check one by one to find out the issues. If your Mac has a startup issue, try the following methods below.
1. Run Repair Disk Utility
01. First thing to fix your mac is to repair disk though the disk utility. In order to get into Disk Utility Mode, we need to access the recovery mode. Shut down your Macbook first. > Turn it on and Press and Hold down Command + R keys together until the recovery mode appears on the screen. > Choose Recovery Hard Drive
02. Please select DISK UTILITY.
03. Select your hard drive on left side bar, and Click on First Aid button. After the process is done, try restart your Macbook. It could solve the startup issues. If it didn’t work, let’s try the next method.
2. Safe Mode
01. If your Mac doesn’t have enough space to boot up to MAC OS X, this could be happened. So let’s access safe mode and try to remove useless files. Please shut down your macbook first. > Turn it on and Press and Hold Down Shift Key until you get the Login screen.
02. If you successfully boot into safe mode, try to find and delete or backup files that uses a lot of space. If it didn’t work for you? let’s try next step.
3. Disable FileVault
01. Try to boot into Recovery Mode. Restart your Macbook or turn it on and Press and Hold Down Command + R keys together until the recovery mode comes up on the screen. > Choose Recovery Hard Drive.
02. On the Menu, Go to Utilities > Terminal
03. Type sudo fdesetup disable in the command terminal. This Process will take some time. You can check the process status using this command – sudo fdesetup status
04. Try to reboot your Macbook after the process is done.
4. Boot into Single User Mode or Verbose Mode
Shut down your Macbook First. Once you turn it on, Press and Hold Down Command + S to boot into Single User Mode and Command + V to boot into Verbose Mode. (To leave Single User Mode, Type reboot in the prompt).
5. SMC & PRAM Reset
SMC RESET
01. Shut Down your Macbook and Connect the MacSafe adapter into your Macbook.
02. Press Shift + Control + Option + Power keys at the same time.
03. Turn your Macbook On.
PRAM RESET
01. Shut Down your Macbook.
02. Press and Hold Down Option + Command + P + R Keys.
03. Press the Power button to turn on, but Keep holding Option + Command + P + R keys.
04. You will hear another beep starting sound. When you hear the second beep starting sound, you can release the held keys.
PRAM RESET for LATE 2016 MACBOOK PRO
01. Turn off your Macbook.
02. Press and Hold Down COMMAND + OPTION + P + R keys.
03. Now turn your macbook on and keep holding down held keys (COMMAND + OPTION + P + R)
04. Keep holding down COMMAND + OPTION + P + R for 20 seconds.
6. Re-Install Mac OS X
If all of above ways didn’t work, here is one last thing to do. Re-installing Mac OS X. But re-installing Mac OS X will delete all of your data, so please be careful before starting. (How to re-install Mac OS X)