# Unable to boot - possible MBR/GPT problems?



## Trentham (Nov 9, 2002)

I've been working on a laptop where the video had died and so I replace the motherboard. It was an earlier version of the mobo but when I got it installed the computer now showed signs of life and all the bits were working except that it refused to boot.

The disk contains windows 10, although it had previously been on Windows 8 and everything looks OK; I can access the main partition normally (from the recovery environment and when mounted on another machine) but when I try to boot it says 'Reboot and select proper boot device'.

I tried a few things with bootrec; fixboot and fixmbr (which may have messed thing up now!) but all to no avail. I'd also tried rebuilding the BCD to no effect (and have now restored it to its previous state).

My concern is that the disk is GPT and possibly the motherboard only supports MBR. Is this possible and how can I check?

Assuming this is the case, is there any way I can fix it? I've looked in the BIOS and can see no option to flash it to a later version (it says it's InsydeH20 rev 3.7 - not one I've ever heard of).

Is it possible to convert the GPT drive to MBR? it currently contains too many partitions but I assume that some could be lost/made logical. Relevant ones would appear to be:-

MainDrive NTFS 919GB - containing the windows installation
System NTFS 450MB - contains (among a few other things) a boot folder
-unnamed- FAT32 260MB - contains the EFI folder
Recovery NTFS 10GB - I assume recovery of the original Win8 system
There are a couple of other partitions which seem to use some space but, as far as I can see (using attrib) contain no files or folder - perhaps they're VERY hidden?

I'll try and include an image of the partitions (from easeus).

I'm very experienced with working with these highly technical issues but this one is (so far) outside my experience. Any ideas?

Sorry if this isn't the best area to post into but it's not obvious where it should go!


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## plankton23 (Feb 8, 2018)

Trentham said:


> I've been working on a laptop where the video had died and so I replace the motherboard


I'm surprised you got it to do anything because when you do that, you have to do a clean install of the OS. This is required because of the chipset driver and the rest of the hardware drivers as they are different from old mobo.



Trentham said:


> My concern is that the disk is GPT and possibly the motherboard only supports MBR. Is this possible and how can I check?


This makes no difference to the OS and how it operates and has nothing to do with mobo......GPT and MBR are related to partitions and how many you can have. Here's a good read on the subject.
https://www.linkedin.com/pulse/whats-difference-between-gpt-mbr-when-partitioning-drive-tiwari



Trentham said:


> Is it possible to convert the GPT drive to MBR?


The only way to do that is a clean install. If it were the other way (MBR to GPT) it's a no problem thing to do.

So, when every you replace a mobo or CPU or a combo of both, it's required that you do a clean install of the OS. This has to do with how MS associates the ID of mobo/cpu with OS license/key.


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## Macboatmaster (Jan 15, 2010)

In view of this


> I'm very experienced with working with these highly technical issues


I will only deal with the problem in brief mention rather than explaining steps in detail, as would be required for the inexperienced user.

1. The drive is as you say most definitely formatted GPT
On a UEFI firmware the computer would boot from the firmware and control would then be handed at the appropriate stage to the Windows Boot Manager
That is on the FAT partition of the GPT partitioned drive

2. This


> InsydeH20 rev 3.7 -


is a UEFI firmware

3. IF the firmware was ONLY MBR capable - the traditional BIOS then it would not be capable of finding a boot configuration data on the present Windows installation, as it does not exist - it is a BCD built on a GPT with as I said a FAT partition that is the partition from which enables the firmware to see the boot device.

4. The converse applies in so far as a UEFI firmware cannot, unless legacy mode is enabled hand control to a BCD on a windows installation when that BCD is configured for an MBR

5. What changes you have made or now reverted I do not of course know

6. Apologies if it is a little too basic - but is the drive seen in the UEFI setup
Is the boot device option applicable to the drive
How is the UEFI configured

7. Other details have been mentioned by *plankton23*
It MAY not be necessary to make a clean install - although that is very likely the easier method.
I am not certain from your post if this drive with Windows 10 (upgraded from 8) was originally in this laptop.


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## managed (May 24, 2003)

Please post the full make and model of the laptop and details of the original and replacement motherboard differences.


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## Macboatmaster (Jan 15, 2010)

Trentham
I think you have seen the replies
May we receive a response from you please


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## Trentham (Nov 9, 2002)

Thanks for some good pointers, though I'm not sure that plankton23 can be right with, "you have to do a clean install of the OS. This is required because of the chipset driver and the rest of the hardware drivers", since it is possible to boot OS's from CD's, etc. without the need for drivers. Drivers are loaded in once the OS is available and bootable, surely.

In my case the mobo was almost the same as the original, not quite the same but of the same family and so the hardware can be expected to be much the same.

The BIOS (OK, UEFI) does show the disk drive as present but declines to boot from it. There are no options showing relating to legacy mode or similar and, from what I've read, to get at extra options requires flashing it and I'm not sure that's the best (easiest) way to go.

Aomei partition manager does offer options to convert mbr to gpt and vice versa but I did a test on a spare disk which could originally boot and converted mbr -> gpt and then back again and it could no longer boot. It only had a single partition but clearly something got changed in the process so without deeper examination of the underlying structures, I'm not going down that route.

I suspect that I'll end up just reinstalling the system. It would be nice to put things back the way they were so it'll be interesting to see whether I can install Win10 and then reinstate a clone of the original windows partition. Some more experimenting will be required.


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## Trentham (Nov 9, 2002)

The laptop is a Toshiba L875-12V and around 5 years old.
The original; mobo was H000043490 and the replacement is H000041510
Physically the motherboards look the same and I believe the disk drive (1TB) is what it came with originally, although in those days it sported Windows 8.

Sorry about the delay in replying but I've been doing a lot of researching and testing as well as looking after my grandkids!


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## plankton23 (Feb 8, 2018)

Trentham said:


> though I'm not sure that plankton23 can be right with, "you have to do a clean install of the OS


Yes...when you replace mobo and or CPU....as the drivers for the "NEW" mobo will be different.


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## Trentham (Nov 9, 2002)

plankton23 said:


> Yes...when you replace mobo and or CPU....as the drivers for the "NEW" mobo will be different.


I've never had to do that in the past just to get the computer to boot after replacing a motherboard. It's true that many functions will not work (ethernet, wireless, sound, etc) and drivers need to be installed but that can only be done once it has booted into windows.

In this case, however, I'm expecting all the drivers to be perfectly adequate to drive the hardware since it's fundamentally the same type of motherboard with the same chipsets, etc - or so I'd hoped.


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## plankton23 (Feb 8, 2018)

Trentham said:


> I've never had to do that in the past just to get the computer to boot after replacing a motherboard. It's true that many functions will not work (ethernet, wireless, sound, etc) and drivers need to be installed but that can only be done once it has booted into windows.


This is the risk one takes....as you pointed out some stuff doesn't work. If your lucky enough to get the drivers installed and then function properly...then good. But 99% when taking that route there is always the inevitable failure of some component or system stability and functionality. It may not show up right away but it always does. The only time that this is not required or recommended is if the mobo and or CPU are exactly the same make/model and version.

If you ask any certified IT tech they'll tell you the same thing....it's a requirement and highly recommend that you do so. Most of the time it has to do with the licensing aspect with MS.

It's your system and you can go about it as you please.....this is just some friendly advice.


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## Trentham (Nov 9, 2002)

plankton23 said:


> If you ask any certified IT tech


Ah, like me ;-)

I'm not disputing the need to install drivers to get the system working properly, merely that it's not necessary in order to be able to boot into an OS since they all come with a basic set of drivers to get basic things going. In fact the equivalent process to replacing a motherboard is to put in a different disk, i.e. one which has stuff already installed on it. Although it can boot, it's not going to do very well running all the hardware without the correct drivers.

What my original problem was that the disk drive/Windows wouldn't boot in the first place. The failure to boot is not the lack of correct drivers but, I suspect, the inability of the system to handle GPT drives - though I'm not sure how to test this theory. I've done a successful Win10 install to a spare disk (which installed as MBR) so maybe convert to GPT and see if it still works or if that kills it?


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## Macboatmaster (Jan 15, 2010)

1. Hold down F12 key power the computer on. release F12 after initial power on
You should see the One time boot menu - *what options are shown please
IF the option Windows Boot Manager is shown that is what you want*

2. You may if you wish proceed as here
Boot the computer from a windows 10 installation media
Make it from here
https://www.microsoft.com/en-gb/software-download/windows10

either usb or dvd
When you have it booted from that
Click Repair your computer

Then on the window that opens click troubleshoot
advanced options
startup repair

DO NOT change that drive to MBR using diskpart or Aomei or anything else.

If that does not work post back and I will give you the next steps
If you make any other changes you may NOT recover from this.

That laptop came with Windows 8 64 bit pre installed
IT must be UEFI firmware

http://www.toshiba.co.uk/discontinued-products/satellite-l875-12v/

This


> The BIOS (OK, UEFI) does show the disk drive as present but declines to boot from it. There are no options showing relating to legacy mode or similar and, from what I've read, to get at extra options requires flashing it and I'm not sure that's the best (easiest) way to go.


IS INCORRECT - please be assured that all computers sold with 8 pre installed on UEFI firmware MUST provide a way of booting to a legacy device.
You have not looked at the correct page of the firmware
That said it is irrelevant in your case
UNLESS you have changed the settings


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## plankton23 (Feb 8, 2018)

Trentham said:


> I'm not disputing the need to install drivers to get the system working properly


Me either, the point is a clean install for new mobo. Not just plop in the old HDD and expect it to boot up with new mobo. It may or may not....most likely it wont.


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## Macboatmaster (Jan 15, 2010)

The problem is more than likely the disk controller driver on the different motherboard
That if the settings are correct for the UEFI boot with the correct AHCI etc mode is the cause of the
inaccessible boot device error etc.

Often a startup repair in Windows 10 from the install media will find the correct driver
The startup repair in 10 is better than in previous editions
It basically

Startup Repair will scan your system and analyse the various settings, configuration options, and system files as it looks for corrupt files or botched configuration settings. More specifically, Startup Repair will look for the following problems:

Missing/corrupt/incompatible drivers
Missing/corrupt system files
Missing/corrupt boot configuration settings
Corrupt registry settings
Corrupt disk metadata (master boot record, partition table, or boot sector)
Problematic update installation
IF startup repair does not work there are more complicated ways of attempting to circumvent the problem before proceeding to a clean install

There will be problems caused by other incorrect drivers, but these can be sorted out after windows loads
The problem that is stopping it even getting to the first stage is as I said -
incorrect settings in firmware for the process to even get as far as attempting to load windows
OR the driver for the disk controller cannot be found in the boot process


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## Trentham (Nov 9, 2002)

Macboatmaster said:


> what options are shown please


It just shows HDD/SDD, USB, ODD & LAN - no Windows boot option

Startup repair was the first thing I tried but to no avail. I might let it have another try but have no reason to believe it will be any different.

And there really is nothing I can find in the firmware relating to legacy mode.



Macboatmaster said:


> That laptop came with Windows 8 64 bit pre installed
> IT must be UEFI firmware


But remember that this is no longer the motherboard that came with the machine



Macboatmaster said:


> incorrect settings in firmware for the process to even get as far as attempting to load windows


Which is why I've been originally looking down the line of 'does this firmware really support GPT?', though you say InsydeH20 rev 3.7 is UEFI firmware.



Macboatmaster said:


> OR the driver for the disk controller cannot be found in the boot process


I've been able to do many other disk related processes like a new install of Win 10 - which ended up as an MBR disk; just nothing that could boot from a GPT drive.

Obviously (is it obvious?) the drivers put out by Toshiba for the laptop are not motherboard dependent so I maybe need to find drivers for that specific issue (H000041510), which I've been unable to do.

Needless to say, my attempt to restore (using Macrium) the windows partition into a working Windows partition did not work. It ended up converting the MBR disk to GPT. That was a (v ery) long shot anyway.

It goes without saying that all the various tests and experiments have been performed on other, spare disk drives


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## Macboatmaster (Jan 15, 2010)

Try this
troubleshoot
advanced options
cmd prompt

type
*bcdedit /set {default} safeboot minimal*

*note it is { and not [

*
see if it reports operation completed successfully

Come out of that remove the installation media
try again see if it will load windows


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## Trentham (Nov 9, 2002)

Macboatmaster said:


> bcdedit /set {default} safeboot minimal


Much the same as when I tried to do any other bcdedit commands, I get, "The boot configuration data store could not be opened. The requested system device cannot be found"

So I mounted the fat32 partition as a drive and used the bcd store in \efi\microsoft\boot, which obviously did allow me to set safe modet though, not surprisingly, it still came up with the boot failure, "reboot and select proper boot device". After all if it can't find a boot device, trying to boot safe mode isn't going to be any better.

Although it repeatedly refuses to boot from a GPT disk, diskpart is quite capable of showing all the partitions and even mounting them in recovery command prompt. I'm not sure what that tells me; would I be able to do that with BIOS rather than UEFI?


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## Macboatmaster (Jan 15, 2010)

If the reason it cannot find the boot device is that the disk controller driver is not the correct one, then Safe Mode loads a set of generic drivers
Therefore by forcing a Safe Mode boot only the result MAY have been different



> After all if it can't find a boot device, trying to boot safe mode isn't going to be any better.


Good luck with it

*IMHO it is unworthy of my further effort*
Obtain your data from the drive and then make a clean install from the installation media
If there was a Microsoft account associated with the install then the change of motherboard, as you may know, still allows activation, automatically in most cases

If not you will have to contact Microsoft and request activation .
https://support.microsoft.com/en-gb/help/20530/windows-10-reactivating-after-hardware-change


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## Trentham (Nov 9, 2002)

Thanks for your efforts. much appreciated and I've increased my knowledge regarding UEFI, BIOS, GPT and MBR.



Macboatmaster said:


> Obtain your data from the drive and then make a clean install


Whilst I've been trying to get things going, I've been setting up a fresh installation on another disk so I'll see how that goes and whether I can activate it or whether I'll just end up installing a different OS.


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