1.    19 Dec 2015 #1
    Join Date : Nov 2015
    Posts : 5
    Windows 10 Pro 64-bit

    Can't re-establish Master Boot Record on my Windows 10 Boot drive


    I'm perplexed and frustrated. I have a legacy 64 bit dual core desktop (ASUS mobo). I have several Sata hard drives in it with the 4th partition of my 1 Terabyte drive containing my Windows 10 Professional boot OS. After converting another similar legacy machine to a NAS device I took the old Windows 10 32 bit OS drive from it and tried booting the ASUS machine with it. Needless to say, the OS didn't like it and reverted to Windows 10 Pro Insider Preview edition (build 11082).

    Here's the kicker. When I tried to restore the boot drive to the original one for this machine the master boot was missing.
    I had just formatted another partition on the same drive that had contained a Windows7 installation that had failed. This partition may have contained the master boot record. So I booted to a command prompt from a USB drive and successfully ran the following commands:


    • bootrec /RebuildBcd
    • bootrec /fixMbr
    • bootrec /fixboot
    • bootsect /nt60 SYS
    • bootsect /nt60 all


    After that the BIOS just says "An operating system wasn't found. Try disconnecting any drives that don't contain an operating system"

    This disk and OS are on the original machine it used to run on. As I understand it, Windows 10 tries to record it's key to somewhere in the BIOS. But the BIOS on these old machines don't provide such a facility. I don't understand what Windows 10 OS does with the key in this instance. If it was recorded in the BIOS then I'd presume that the other Windows 10 drive I attempted to use would have found it and used it. Or perhaps not, since it didn't like the new environment.

    So what I'm looking for is a way to get my original Windows 10 to boot again on the same machine it had always work on before, from the 4th partition of the 1 terabyte drive I'm using. Any help is appreciated.
    Last edited by Rawl214; 19 Dec 2015 at 23:52.
      My ComputerSystem Spec
  2.    30 Dec 2015 #2
    Join Date : Nov 2015
    Posts : 5
    Windows 10 Pro 64-bit
    Thread Starter

    It's pretty quiet here. It seems no one has read my plea for help. I guess I just have to wait for my bottle to wash-up on some distant shore.
      My ComputerSystem Spec
  3.    30 Dec 2015 #3
    Join Date : Jul 2015
    Posts : 9,551
    Windows 10 Pro

    First, Windows 10 does not write anything to bios. That is nothing more than an urban myth.
    Second, your OP was confusing as heck to read.
    Third, hopefully the solution to your problem:

    1. On an operating computer, install Macrium Reflect Free.
    2. Use that to make a Macrium Reflect Free rescue USB/DVD/CD.
    3. On the troubled computer, disconnect all hard drives except the one containing the Windows you want to boot. I would recommend making sure that hard drive is connected to the first SATA port of the motherboard.
    4. Boot the computer from the Macrium Reflect Free rescue USB/DVD/CD.
    5. Run the fix boot (or startup) problems utility found under the restore menu.

    Good luck!

    Macrium Reflect Free
      My ComputerSystem Spec
  4.    30 Dec 2015 #4
    Join Date : Apr 2014
    Posts : 3,361
    W10 Pro x64/W7 Ultimate x64 dual boot main - W10 Pro Insider Preview/W7 Pro x64 - remote pc

    Hello there! Rawl214 Welcome to the Ten Forums!

    Around the holidays you should be a little more patient as many are away visiting friends and family if not taking breaks from any school they attend.

    Now for any Asus board not having Sata 3 ports mixed with Sata II such as a much older board when unplugging all drives without any OS being set up in a dual or multi boot as well as reserving the option to add new boot entries into the 10 not previous version's BCD store the OS drive by itself is what is left plugged in to avoid seeing the 10 boot files and temp installation folders end up on the wrong drive. Since the 64bit 10 Pro Insder Preview build was added onto the same drive after W7 and later the 32bit 10 Insider Preview build was added to follow 7 which was either on the first primary partition or second if the System Reserved partition was initially created the later 10 Pro install simply over wrote the previous mbr information on the 7 primary!

    This is where splitting up a single drive to pack on the various OSs can lead to problems where you may end needing to see either an Upgrade to Repair type install in order to not so much repair 10 but to see the boot sector written fresh again. Or you can opt to see a fresh install of 10 using that to replace the previous 7 install. Here the 10/7 dual boot is actually across two separate drives where the 7 was simply unplugged originally for trying 10 out and then later actually buying 10 to keep both versions on permanently. The present 10 install however was the latest Insider build replaced by upgrade with the Threshold 2 update in November.

    Now for an updated Asus board with Sata 3 ports as well as Sata II the first thing to note will be the S3 ports will appear as Disk 0 and Disk 1 when only having two S3 type ports. Plugging the OS hopefully an S3 not Sata II or SSD into the first port will see that made Disk 0. If you are running a Sata II drive however once the other drives are replugged back in you will need to move the OS drive to the top of the list in the Advanced section Boot order in order to see that made the default OS drive. Any S3 drives will automatically be then seen as Disk 0 and Disk 1 despite having a Sata II OS drive set at the top as the default.

    Out of curiosity if not a typo on your part where did you come up with a "build 11082" when the last four builds since the July 29th launch date for 10 are 10240, 10565, 10576, 10586 version 1511 which also applies to the Threshold 2 Update in November? No new builds are scheduled for 2015 with 2016 at the doorstep at this time.
      My ComputerSystem Spec
  5.    30 Dec 2015 #5
    Join Date : Aug 2015
    Penn's Woods
    Posts : 1,275
    Windows 10 Home

    Quote Originally Posted by Night Hawk View Post
    ..Out of curiosity if not a typo on your part where did you come up with a "build 11082" when the last four builds since the July 29th launch date for 10 are 10240, 10565, 10576, 10586 version 1511 which also applies to the Threshold 2 Update in November? No new builds are scheduled for 2015 with 2016 at the doorstep at this time.
    11082 IS latest Insider build (as OP specified), Night Hawk. At least I hope it is, as that's what's installed on my Insider partition...
      My ComputerSystem Spec
  6.    30 Dec 2015 #6
    Join Date : Apr 2014
    Posts : 3,361
    W10 Pro x64/W7 Ultimate x64 dual boot main - W10 Pro Insider Preview/W7 Pro x64 - remote pc

    You have it right! I missed the announcement a few weeks back. Been tied up with other things lately including screening several softwares! Only found one or possibly two out of a lengthy list for a project I got too busy with I guess?!

    The situation with the split drive reminds me only too well about the split I made on the second remotely controlled pc here when only having a single 7 drive in the mini tower at the time and splitting that up for the Insider Preview builds to follow the 10240 release. Unfortunately 10 will continue to remain temp installs there however since no 10 drivers can be found for the usb wireless WiFi adapter! The mini case was built to be portable you can carry from room to room for temp set ups.

    Once a second drive was added in being one of a pair of 1tb storage drives previously seen on the main I split that up for a small 7 primary I restored a 7 image to and attempted to move the 10 Insider primary forward and found that wouldn't boot having forgotten 7 was wiped there which is why a second clean install of 10 was then seen to once the entire was wiped to simply create a fresh single primary on the old 500gb now host/boot drive while 7 Pro x64 still remains the permanent resident for the time being. The new entry for 7 was simply added into the fresh 10 install once the second drive was plugged back in.
      My ComputerSystem Spec
  7.    31 Dec 2015 #7
    Join Date : Nov 2015
    Posts : 5
    Windows 10 Pro 64-bit
    Thread Starter

    Thank you NavyLCDR for your very helpful guidance with this problem. I think I'm becoming a fan of Macrium Free. Big save for me. Thanks again.

    Also thank you to Night Hawk for your detailed explanations. I'm not sure I've been able to comprehend all of it yet. A few more readings of it and I'm sure more useful info with stick in the grey matter upstairs.

    Now that the correct windows 10 installation is booting as it should, next step is to start reconnecting the extra drives back up and hoping they'll all behave predictably and manageably.
      My ComputerSystem Spec
  8.    31 Dec 2015 #8
    Join Date : Apr 2014
    Posts : 3,361
    W10 Pro x64/W7 Ultimate x64 dual boot main - W10 Pro Insider Preview/W7 Pro x64 - remote pc

    Once you replug the other drives and if you have any preference for which drive sees which drive letter you will want to right click on the Start button to select the Disk Management tool option. Unfortunately drive letters do get bumped around at times.
      My ComputerSystem Spec

 


Similar Threads
Thread Forum
Installation & Upgrade Boot from USB Drive on Windows 10 PC
How to Boot from a USB Flash Drive in Windows 10 This tutorial will show you how to boot from a USB drive at boot or from within a Windows 10 PC or Surface. If you have fast boot or ultra fast boot enabled in your UEFI firmware settings, then...
Tutorials
windows 10 clone hard drive will no boot
Hi I cloned my hard drive a Seagate 2T to a WD 2T using acronics software I removed my Seagate drive and plugged in my WD drive in the same spot and system would not boot tried using windows 10 repair disk no luck plugged the Seagate drive back...
Backup and Restore
Laptop doesn't boot because OS is on D: drive instead of C: drive
My laptop doesn't boot because OS is on E: drive instead of C: drive 43364 When I try to boot it up (it somehow boots up as windows 8.1 instead of my OS windows 10), it gives a BSoD and shows the error code 0xc000021a. I created a bootable...
General Support
Easiest way to remove Windows and boot files from drive
I have two drives with files on them and want to make one drive A inactive(remove windows) so that I can make the other drive have windows 10. What is the easiest way to do that without removing or formating Drive A.
General Support
Can't boot USB drive with x64 windows installer
So heres the deal - whenever I try to install a 64 bit Windows 10 copy from a flash drive, I get stuck on the 4 blue squares, with no white dots spinning. Then after about 10 seconds the PC restarts. I have tried the official way with the media...
Installation and Upgrade
Our Sites
Site Links
About Us
Windows 10 Forums is an independent web site and has not been authorized, sponsored, or otherwise approved by Microsoft Corporation. "Windows 10" and related materials are trademarks of Microsoft Corp.

Designer Media Ltd
All times are GMT -5. The time now is 19:48.
Find Us
Twitter Facebook Google+ Ten Forums iOS App Ten Forums Android App



Windows 10 Forums