Just check for these following and go through these steps to find the issue or problem and resolve it.
Check if your MacBook is connected to AC power.Press and hold the power button or touch ID of the Mac for about 10 seconds.Press and release the power button if you see no change.
Turn off Mac. Turn it on and press & hold Command+R to start macOS recovery. To repair startup disk use Disk Utility. Reinstall macOS if no error found.
If Mac stops at prohibitory symbol
If Mac stops at prohibitory symbol
Select setup disk from setup disk preference and reset NVRAM. If mark persists, turn off the Mac & repeat the process you did when during prohibitory symbol.
If Mac stops at a question mark-
Option with gear -
Select startup disk & click continue to startup. To open macOS recovery click options > continue. Reinstall macOS. To repair or erase disk use disk utility. Select shutdown.
Option with gear -Select startup disk & click continue to startup. To open macOS recovery click options > continue. Reinstall macOS. To repair or erase disk use disk utility. Select shutdown.
Turn off the Mac & then turn it on. If issue persists, turn off Mac & unplug all accessories(printers, USBs, etc). Now try again. Still issue persists, reinstall macOS.
Turn off the Mac & then turn it on. If issue persists, turn off Mac & unplug all accessories(printers, USBs, etc). Now try again. Still issue persists, reinstall macOS.
Mac screen stops at apple logo-
If Mac is using firmware password ( such as any external drive or macOS recovery ). To continue, enter the firmware password.
If a lock icon appears while startup using another disk or volume.
If the issues aren't resolved by following the mentioned steps, contact Apple Support. Sign in to your Apple ID to save your time and get get personalized solution.