Restore Lost or Deleted Hard Disk Drive Partition - Windows 10 will not boot lost MBR

Repair Master Boot Record (MBR)
Please understand this worked for me, if you don't feel comfortable trying any of these steps stop now.

You could place the drive into another computer by means of a USB dock backup your files, then reinstall windows 10 once backup complete or clone the drive so that you have a backup in case this doesn't work, that's what I did.

I used Acronis backup and created a back up of my 3.5" drive onto an SSD drive, yes the lost partition was still lost/deleted but once fixed I could apply the same method to the SSD drive.

So you have lost or accidentally deleted the system reserved partition, in my case D drive.

This happened to a work college's PC, he accidentally deleted what he though was an unneeded partition.

You will need to download the correct version of the windows 10 recovery tool either 32bit or 64 bit for your system.

To check your system click on windows explorer

Right click on This PC, Then Properties

As you can see this is a 64bit system

Media creation Tool : https://www.microsoft.com/en-us/software-download/windows10

or

http://go.microsoft.com/fwlink/?LinkId=691209


In my case I was able to create a recovery USB drive from another PC running windows 10 64bit.

Now go to search type Create a recovery drive, Click on the Create a recovery drive App, Press Yes if UAC  is prompted

Click Next

The system will check to see the size of the USB drive needed.

WARNING It will delete everything on the drive

Insert an empty USB drive, in my case it needed to be at least 8Gb, then click next

Start the computer and press Delete to enter the bios, each computer is different so check motherboard specs to see you what key you need to press to enter the bios

Computer manufacturer boot menu : https://craftedflash.com/info/how-boot-computer-from-usb-flash-drive

Once in the bios select boot tab, disable fast boot.

Change the order so that the USB drive is at the top first boot

Press F10 to save and exit

To recover or repair the drive I tried Startup repair in the Advanced Options but that was unsuccessful

In the advanced options I choose Command Prompt

Then typed the following


bootrec /rebuildbcd

bootrec /fixmbr

bootrec /fixboot

bcdboot c:\windows /s c:

exit

Reboot and remove USB drive

Booted fine as this is the first boot it will take some time, you may need to restart a few times.

I then applied the same method to the SSD drive and rebuilt the MBR bothe drives worked fine.