Boot from Windows media (Windows 7, 8, 10).
Select the correct time and keyboard type (or just continue).
Click Repair your computer in the lower left corner.
Select Troubleshoot from Choose an option screen.
Click Advanced options in Troubleshoot screen.
Select Command Prompt.

Use the following commands to diagnose and fix BCD store related errors:
bootrec /fixmbr
bootrec /fixboot
bootrec /scanos
bootrec /rebuildbcd

If you are deploying WIM images via a WinPE command shell you can use the following command to configure the BCD store for first use manually:

C:\Windows\system32\bcdboot C:\Windows /s S: /f ALL

Where [C:] is the volume holding the Windows installation (System partition) and [S:] is the volume containing the EFI folder (Reserved partition).  You can use diskpart ‘list volume’, ‘select volume’ and ‘assign letter=’ to set the correct drive letter for the correct partition.

Reset PRAM [Command]+[Option]+[P]+[R]

PRAM stands for parameter random access memory, which can contain settings such as speaker volume, screen resolution, startup disk selection, and recent kernel panic information. Performing a PRAM reset can fix a number of issues, such as wifi connectivity, drives not showing up or screens not adjusting properly. To do a PRAM reset, all that has to be done is turning the Mac device on and holding Command + Option + P + R until the machine chimes a second time. This process should be done for a longer amount of time on a Late 2016 MacBook Pro because it doesn’t have a startup chime. However, PRAM resets are actually a thing of the past. Today the majority of Macs in use; ones manufactured after 2008, actually primarily use NVRAM to store many of these settings. A PRAM reset and a NVRAM reset are mostly the same, it resets less volatile ram to default factory settings, fixing a number of potential issues. NVRAM stands for non-volatile random access memory and is reset in the same manner as PRAM is.

Reset SMC [Shift]+[Option]+[Control]+Power On

SMC stands for system management controller, this is only on Intel-based Macs. SMC resets reset this controller which is a part of the machine that deals with hardware and power management. This system management controller reset can fix problems dealing with the fans, lights, power and system performance.. There are a variety of ways to reset the SMC depending on the kind of Mac you’re working with. A desktop mac, such as a Mac Pro, Mac Mini, or iMac requires disconnecting the power cord from the machine, waiting 15 seconds, plugging it back in, waiting another 15 seconds and then turning the Mac back on. With a Mac laptop with a non-removable battery, shut the Mac down and connect the Mac to its power adapter. Hold shift, option and control on the left side, then press the power button, release all keys and then turn the Mac on normally. For Mac laptops manufactured 2008 or before with removable batteries, turn the machine off, disconnect the power cable, remove the battery. Press the power button and hold for 5 seconds. Put the battery back in, reconnect its power cable, and turn the Mac back on.

Recalibrate smart battery charge indictor

Your Apple MacBook’s battery has a small chip built in to it that relays information to your computer about its current charge and how long the laptop can run before recharging. You’ll need to calibrate this chip by charging, fully draining and then charging your battery again every few months to maintain an accurate readout. This procedure is simple, but draining your MacBook’s battery can take some time, especially if the battery is new. If you aren’t content to simply deplete the power with hours of normal use, you can hasten the process in several ways.

• Unplug power cord.
• Play a DVD or YouTube video full screen.
• Maximum brightness.
• Turn on Wi-Fi and Bluetooth.
• Disable power management / power saving features.

Safe mode

Restart your device.  Immediately after you hear the startup tone, press and hold the Shift key. Do not press the Shift key before you hear the startup chime. You would ideally hit Shift as soon as possible after you hear the startup tone.  If you use OS X’s FileVault feature to encrypt the entire startup disk, release the key when your Mac prompts you to unlock the disk, type in your password and press Enter.  Release the Shift key when the desktop or OS X’s login screen appears.  To exit Safe Mode, restart your Mac like you normally would.

Verbose Mode

Verbose Mode is like normal booting mode, with one exception: instead of watching the progress bar filling or the spinning indicator spinning, it gives you peek under the hood and see the output of what’s happening every time the system starts up.  As such, Verbose Mode is useful for troubleshooting software issues you may be experiencing with macOS or third-party apps. It’s also indispensable for software development.  Verbose Mode does little to solve any boot problems but may help to gain an insight as to why and where exactly in the boot process the problems reside.

To startup your Mac in Verbose Mode, follow these simple steps.   Restart your device.  Right upon hearing the startup chime, press and hold the Command (⌘) – V key combination for Verbose Mode.  You’ll know that you have successfully entered Verbose Mode when you see white text appear on the screen as if you were in the MS-DOS text mode from the 1980’s, as depicted on the screenshot at the top of the post.  You will automatically exit Verbose Mode when the Mac’s startup process progresses sufficiently and the macOS login screen or desktop appears.