I have been converting my win10 legacy machines to UEFI and ran into an
odd one where the mbr2gpt command did not work. Message was : cannot
find OS partition.

The solution was simply to go into disk management and mark the windows
partition active.

Up until now I thought that the bootable OS must always be on an active
partition.

Anyone have more info . Thanks

On 24/08/2021 21.09, philo wrote:
> I have been converting my win10 legacy machines to UEFI and ran into an
> odd one where the mbr2gpt command did not work. Message was : cannot
> find OS partition.
>
> The solution was simply to go into disk management and mark the windows
> partition active.
>
>
> Up until now I thought that the bootable OS must always be on an active
> partition.

Not really.

> Anyone have more info . Thanks

If you have several operating systems, it is easy that the Windows
partition is not marked bootable (active), nevertheless it is booted by
the boot manager.

--
Cheers, Carlos.

Aha!
Thank you.
I had a Linux drive in the machine and was having GRUB hand off the boot.
Appreciate your reply.

I put the Linux drive in a legacy BIOS machine.

Just thought of sonething though.
The Windows drive booted fine without the Linux drive in the machine.

From disk management , when I selected the partition, I had the option to make it active...so now that I thinl of it, I'm still stumped.

No other OS's on the drive or in the machine.

On 24/08/2021 22.51, philo wrote:
> Aha!
> Thank you.
> I had a Linux drive in the machine and was having GRUB hand off the boot.
> Appreciate your reply.
>
> I put the Linux drive in a legacy BIOS machine.

A typical method with Grub is precissely to mark the partition that
contains Grub, which also typically is also the Linux root, bootable.

The problem this poses, is that Windows can fail when doing some updates
with obscure error messages. There is a trick for that, but it is not
your case now.

You can examine the current boot status (mostly from the Linux point of
view) by running this script in Linux:

https://github.com/arvidjaar/bootinfoscript/raw/master/bootinfoscript

It generates a long text file with generous information.

If you have a single disk with Windows only, legacy bios mode, that
windows partition should be active, and the bios should have that disk
as the boot one.

I have no experience in migrating Windows from bios to uefi. Linux, yes,
I have done it (I had to insist a bit, but got it done).

--
Cheers, Carlos.

philo wrote:
> Just thought of sonething though.
> The Windows drive booted fine without the Linux drive in the machine.
>
> From disk management , when I selected the partition, I had the option
> to make it active...so now that I thinl of it, I'm still stumped.
>
> No other OS's on the drive or in the machine.

Linux does not use the Boot Flag.

And while much of GRUB appears to be using GUIDs,
during grub_install, it uses a device identifier
for one of the boot stages. This is why it is *still*
possible to have a Linux Surprise, caused purely by
pushing partitions around willy-nilly. You might be
fooled, by looking at your /etc/fstab, into thinking
the details noted in the fstab are the "whole story".
They aren't.

*******

Back in Windows, if you look at Disk Management, one
partition can say "System", another partition can say "Boot".
Two partitions can play a part. Or, both can be
squished together onto the one partition. There is
no problem having "System" "Boot" printed on a single
partition.

The item marked "System" is used for booting (boot menu).

The item marked "Boot" is the system partition (the OS).

The "System" partition then, should have the
Boot Flag set on it.

When Windows is booted, the Disk Management screen
can help you determine how these things are defined.

Before any experiment, you might take detailed closeup
pictures of Disk Management, so you can see all those
labels.

Paul

System us up and running just fine once I converted to gpt and used uefi.

Since the system booted fine when it was MBR and the Windows partition was not active. How could it have booted?

On 24/08/2021 23.24, Paul wrote:
> philo wrote:
>> Just thought of sonething though.
>> The Windows drive booted fine without the Linux drive in the machine.
>>
>>  From disk management , when I selected the partition, I had the
>> option to make it active...so now that I thinl of it, I'm still stumped.
>>
>> No other OS's on the drive or in the machine.
>
> Linux does not use the Boot Flag.

It can :-)

If you place on the Master Boot Record (the MBR) a generic boot code
(typically, an MsDOS or Windows boot), it will search for the partition
marked active and boot it. And that partition contains Grub and boots
Linux subsequently. Or Windows.

Strictly speaking, the flag is not read either by Windows nor by Linux.
It is read by the tiny assembler program that lives in the MBR.

--
Cheers, Carlos.

Thanks Paul.
The only thing that makes sense is that the system partition must have been active.

Disk Management does not actually list the active status.

The only reason I knew the partition was not active was because the "make active" dialog was not grayed out.

philo wrote:
> Thanks Paul.
> The only thing that makes sense is that the system partition must have
> been active.
>
> Disk Management does not actually list the active status.
> The only reason I knew the partition was not active was because the
> "make active" dialog was not grayed out.

I will have to dig up an item from the collection.

Unfortunately, this drive is for the Dell Optiplex
and it's not sitting on a table and has no monitor.

So we can only admire its contents at a distance,
using TestDisk.

https://i.postimg.cc/HWrXpW47/WIN7-two-partition-bitlocker-ready.gif

The left-most partition is System Reserved. It contains
enough materials for the stage of booting after the MBR.

The BootMgr and BCD present the boot menu, which can
include a prompt to "access Bitlocker protected C: ".

By separating the boot materials (disk management "System" label),
the Active partition has just enough materials to prompt
for a password.

The "Boot" partition is the C: which is the right-most partition
in the diagram. It has the Windows partition. The Boot partition
on that C: drive, was made by Macrium and contains Macrium-private
materials, and should not be confused with the real \Boot contained
on the System Reserved.

On versions of Windows 7 which do not support Bitlocker,
"System" "Boot" "Active" can be on one and the same partition,
such that C: does everything.

There is also a procedure available, for moving the vital
content of System Reserved over to C: and removing System Reserved.
This allows a Windows 7 Pro system to be denied Bitlocker
protection, as without the separation in the diagram,
you couldn't prompt for a password.

The picture above is taken from the Windows 7 Pro provided
with Refurbisher machines.

It would have been nice to boot the Dell and take a
picture, but that's too much work :-)

Paul

Thanks Paul.

Now I have a different problem.

It's my wife's second back up machine and I need to sign it back in to her MS account but don't have her p/w.

It's 2am and I don't think I should wake her!

philo wrote:
> Thanks Paul.
>
> Now I have a different problem.
>
> It's my wife's second back up machine and I need to sign it back in to
> her MS account but don't have her p/w.
>
> It's 2am and I don't think I should wake her!

I have some Insider installs with MSA accounts and
because they are autologin (netplwiz), I haven't needed
to enter a password for some time (on boot).

Microsoft removed the tick box from netplwiz on some
upgrade (21H1 ?), and there's some trick to bringing
the tick box back.

If it's password protected, you'll see that as it boots up
and there should be a "power" button in the interface, to
shut it down again, if so. (Either you enter the password,
but if you don't have the password, there should be a power
button so you can shut it down again.)

In any case, tomorrow is another day.

Local accounts can be "flattened" by one of the "become admin
at startup" tricks. But the claim is, those tricks were
removed. There was osk.exe as a trick entry point. Becoming
administrator allows some local accountwork to be done,
but for MSA accounts, those would need a reset procedure
by the owner (as control is likely returned via the email
account used to register them). With the fragile gmail
accounts, this can sometimes be a problem (account closed,
no way to finish password reset).

Paul

On 8/25/21 5:30 AM, Paul wrote:
> philo wrote:
>> Thanks Paul.
>>
>> Now I have a different problem.
>>
>> It's my wife's second back up machine and I need to sign it back in to
>> her MS account but don't have her p/w.
>>
>> It's 2am and I don't think I should wake her!
>
> I have some Insider installs with MSA accounts and
> because they are autologin (netplwiz), I haven't needed
> to enter a password for some time (on boot).
>
> Microsoft removed the tick box from netplwiz on some
> upgrade (21H1 ?), and there's some trick to bringing
> the tick box back.
>
> If it's password protected, you'll see that as it boots up
> and there should be a "power" button in the interface, to
> shut it down again, if so. (Either you enter the password,
> but if you don't have the password, there should be a power
> button so you can shut it down again.)
>
> In any case, tomorrow is another day.
>
> Local accounts can be "flattened" by one of the "become admin
> at startup" tricks. But the claim is, those tricks were
> removed. There was osk.exe as a trick entry point. Becoming
> administrator allows some local accountwork to be done,
> but for MSA accounts, those would need a reset procedure
> by the owner (as control is likely returned via the email
> account used to register them). With the fragile gmail
> accounts, this can sometimes be a problem (account closed,
> no way to finish password reset).
>
>    Paul

While I'm waiting for my wife to wake up so I can finish setting up the
last machine in the house...I did something useful and cleaned up my own
office by putting in a kvm switch.

Now I just have one kb and mouse on my desk .

All our Windows machines are now GPT

The two legacy Linux installations ore now setup as dual boot on the
last legacy machine I have in use...the one I actually use the most.

On 25/08/2021 00:11, Carlos E.R. wrote:
> On 24/08/2021 23.24, Paul wrote:
>> philo wrote:
>>> Just thought of sonething though.
>>> The Windows drive booted fine without the Linux drive in the machine.
>>>
>>>  From disk management , when I selected the partition, I had the
>>> option to make it active...so now that I thinl of it, I'm still stumped.
>>>
>>> No other OS's on the drive or in the machine.
>>
>> Linux does not use the Boot Flag.
>
> It can :-)
>
> If you place on the Master Boot Record (the MBR) a generic boot code
> (typically, an MsDOS or Windows boot), it will search for the partition
> marked active and boot it. And that partition contains Grub and boots
> Linux subsequently. Or Windows.
>
> Strictly speaking, the flag is not read either by Windows nor by Linux.
> It is read by the tiny assembler program that lives in the MBR.

I'm surprised that Philo hasn't responded to you, Carlos.

I'll give him a nudge! 😇

On 8/24/21 6:11 PM, Carlos E.R. wrote:
> On 24/08/2021 23.24, Paul wrote:
>> philo wrote:
>>> Just thought of sonething though.
>>> The Windows drive booted fine without the Linux drive in the machine.
>>>
>>>  From disk management , when I selected the partition, I had the
>>> option to make it active...so now that I thinl of it, I'm still stumped.
>>>
>>> No other OS's on the drive or in the machine.
>>
>> Linux does not use the Boot Flag.
>
> It can :-)
>
> If you place on the Master Boot Record (the MBR) a generic boot code
> (typically, an MsDOS or Windows boot), it will search for the partition
> marked active and boot it. And that partition contains Grub and boots
> Linux subsequently. Or Windows.
>
> Strictly speaking, the flag is not read either by Windows nor by Linux.
> It is read by the tiny assembler program that lives in the MBR.
>
>

Although I finally got the active partition thing sorted out,, due to
putting the drive in new hardware, I lost activation.

Since there was not that much data to back up , I did a fresh install
and all is ok.

This was originally an upgrade from win7 so I know there were a lot of
junk files.

With the fresh install on an ssd it's running better that ever!

On 8/25/21 11:55 AM, David Brooks wrote:
> On 25/08/2021 00:11, Carlos E.R. wrote:
>> On 24/08/2021 23.24, Paul wrote:
>>> philo wrote:
>>>> Just thought of sonething though.
>>>> The Windows drive booted fine without the Linux drive in the machine.
>>>>
>>>>  From disk management , when I selected the partition, I had the
>>>> option to make it active...so now that I thinl of it, I'm still
>>>> stumped.
>>>>
>>>> No other OS's on the drive or in the machine.
>>>
>>> Linux does not use the Boot Flag.
>>
>> It can :-)
>>
>> If you place on the Master Boot Record (the MBR) a generic boot code
>> (typically, an MsDOS or Windows boot), it will search for the
>> partition marked active and boot it. And that partition contains Grub
>> and boots Linux subsequently. Or Windows.
>>
>> Strictly speaking, the flag is not read either by Windows nor by
>> Linux. It is read by the tiny assembler program that lives in the MBR.
>
> I'm surprised that Philo hasn't responded to you, Carlos.
>
> I'll give him a nudge!  😇
>

I hit "reply" rather than follow up.

On the Windows version of Thunderbird I can remove the "reply" tab but
can't seem to do so on Linux.

rep;y tab is for email

follow up is to news group

On 25/08/2021 18:32, philo wrote:
> On 8/25/21 11:55 AM, David Brooks wrote:
>> On 25/08/2021 00:11, Carlos E.R. wrote:
>>> On 24/08/2021 23.24, Paul wrote:
>>>> philo wrote:
>>>>> Just thought of sonething though.
>>>>> The Windows drive booted fine without the Linux drive in the machine.
>>>>>
>>>>>  From disk management , when I selected the partition, I had the
>>>>> option to make it active...so now that I thinl of it, I'm still
>>>>> stumped.
>>>>>
>>>>> No other OS's on the drive or in the machine.
>>>>
>>>> Linux does not use the Boot Flag.
>>>
>>> It can :-)
>>>
>>> If you place on the Master Boot Record (the MBR) a generic boot code
>>> (typically, an MsDOS or Windows boot), it will search for the
>>> partition marked active and boot it. And that partition contains Grub
>>> and boots Linux subsequently. Or Windows.
>>>
>>> Strictly speaking, the flag is not read either by Windows nor by
>>> Linux. It is read by the tiny assembler program that lives in the MBR.
>>
>> I'm surprised that Philo hasn't responded to you, Carlos.
>>
>> I'll give him a nudge!  😇
>>
>
>
> I hit "reply" rather than follow up.
>
> On the Windows version of Thunderbird I can remove the "reply" tab but
> can't seem to do so on Linux.
>
> rep;y tab is for email
>
> follow up is to news group

Indeed! :-)

So what *IS* your response to Carlos?!!

On 8/26/21 3:33 AM, David Brooks wrote:
> On 25/08/2021 18:32, philo wrote:
>> On 8/25/21 11:55 AM, David Brooks wrote:
>>> On 25/08/2021 00:11, Carlos E.R. wrote:
>>>> On 24/08/2021 23.24, Paul wrote:
>>>>> philo wrote:
>>>>>> Just thought of sonething though.
>>>>>> The Windows drive booted fine without the Linux drive in the machine.
>>>>>>
>>>>>>  From disk management , when I selected the partition, I had the
>>>>>> option to make it active...so now that I thinl of it, I'm still
>>>>>> stumped.
>>>>>>
>>>>>> No other OS's on the drive or in the machine.
>>>>>
>>>>> Linux does not use the Boot Flag.
>>>>
>>>> It can :-)
>>>>
>>>> If you place on the Master Boot Record (the MBR) a generic boot code
>>>> (typically, an MsDOS or Windows boot), it will search for the
>>>> partition marked active and boot it. And that partition contains
>>>> Grub and boots Linux subsequently. Or Windows.
>>>>
>>>> Strictly speaking, the flag is not read either by Windows nor by
>>>> Linux. It is read by the tiny assembler program that lives in the MBR.
>>>
>>> I'm surprised that Philo hasn't responded to you, Carlos.
>>>
>>> I'll give him a nudge!  😇
>>>
>>
>>
>> I hit "reply" rather than follow up.
>>
>> On the Windows version of Thunderbird I can remove the "reply" tab but
>> can't seem to do so on Linux.
>>
>> rep;y tab is for email
>>
>> follow up is to news group
>
> Indeed! :-)
>
> So what *IS* your response to Carlos?!!

I did respond. Replies about 90 minutes before you posted this

On 26/08/2021 13:07, philo wrote:
> On 8/26/21 3:33 AM, David Brooks wrote:
>> On 25/08/2021 18:32, philo wrote:
>>> On 8/25/21 11:55 AM, David Brooks wrote:
>>>> On 25/08/2021 00:11, Carlos E.R. wrote:
>>>>> On 24/08/2021 23.24, Paul wrote:
>>>>>> philo wrote:
>>>>>>> Just thought of sonething though.
>>>>>>> The Windows drive booted fine without the Linux drive in the
>>>>>>> machine.
>>>>>>>
>>>>>>>  From disk management , when I selected the partition, I had the
>>>>>>> option to make it active...so now that I thinl of it, I'm still
>>>>>>> stumped.
>>>>>>>
>>>>>>> No other OS's on the drive or in the machine.
>>>>>>
>>>>>> Linux does not use the Boot Flag.
>>>>>
>>>>> It can :-)
>>>>>
>>>>> If you place on the Master Boot Record (the MBR) a generic boot
>>>>> code (typically, an MsDOS or Windows boot), it will search for the
>>>>> partition marked active and boot it. And that partition contains
>>>>> Grub and boots Linux subsequently. Or Windows.
>>>>>
>>>>> Strictly speaking, the flag is not read either by Windows nor by
>>>>> Linux. It is read by the tiny assembler program that lives in the MBR.
>>>>
>>>> I'm surprised that Philo hasn't responded to you, Carlos.
>>>>
>>>> I'll give him a nudge!  😇
>>>>
>>>
>>>
>>> I hit "reply" rather than follow up.
>>>
>>> On the Windows version of Thunderbird I can remove the "reply" tab
>>> but can't seem to do so on Linux.
>>>
>>> rep;y tab is for email
>>>
>>> follow up is to news group
>>
>> Indeed! :-)
>>
>> So what *IS* your response to Carlos?!!
>
>
> I did respond. Replies about 90 minutes before you posted this

Really? I don't see your response to him saying ....

"If you place on the Master Boot Record (the MBR) a generic boot code
(typically, an MsDOS or Windows boot), it will search for the partition
marked active and boot it. And that partition contains Grub and boots
Linux subsequently. Or Windows.
>
> Strictly speaking, the flag is not read either by Windows nor by
Linux. It is read by the tiny assembler program that lives in the MBR.

On 8/26/21 9:14 AM, David Brooks wrote:
> On 26/08/2021 13:07, philo wrote:
>> On 8/26/21 3:33 AM, David Brooks wrote:
>>> On 25/08/2021 18:32, philo wrote:
>>>> On 8/25/21 11:55 AM, David Brooks wrote:
>>>>> On 25/08/2021 00:11, Carlos E.R. wrote:
>>>>>> On 24/08/2021 23.24, Paul wrote:
>>>>>>> philo wrote:
>>>>>>>> Just thought of sonething though.
>>>>>>>> The Windows drive booted fine without the Linux drive in the
>>>>>>>> machine.
>>>>>>>>
>>>>>>>>  From disk management , when I selected the partition, I had the
>>>>>>>> option to make it active...so now that I thinl of it, I'm still
>>>>>>>> stumped.
>>>>>>>>
>>>>>>>> No other OS's on the drive or in the machine.
>>>>>>>
>>>>>>> Linux does not use the Boot Flag.
>>>>>>
>>>>>> It can :-)
>>>>>>
>>>>>> If you place on the Master Boot Record (the MBR) a generic boot
>>>>>> code (typically, an MsDOS or Windows boot), it will search for the
>>>>>> partition marked active and boot it. And that partition contains
>>>>>> Grub and boots Linux subsequently. Or Windows.
>>>>>>
>>>>>> Strictly speaking, the flag is not read either by Windows nor by
>>>>>> Linux. It is read by the tiny assembler program that lives in the
>>>>>> MBR.
>>>>>
>>>>> I'm surprised that Philo hasn't responded to you, Carlos.
>>>>>
>>>>> I'll give him a nudge!  😇
>>>>>
>>>>
>>>>
>>>> I hit "reply" rather than follow up.
>>>>
>>>> On the Windows version of Thunderbird I can remove the "reply" tab
>>>> but can't seem to do so on Linux.
>>>>
>>>> rep;y tab is for email
>>>>
>>>> follow up is to news group
>>>
>>> Indeed! :-)
>>>
>>> So what *IS* your response to Carlos?!!
>>
>>
>> I did respond. Replies about 90 minutes before you posted this
>
> Really? I don't see your response to him saying ....
>
> "If you place on the Master Boot Record (the MBR) a generic boot code
> (typically, an MsDOS or Windows boot), it will search for the partition
> marked active and boot it. And that partition contains Grub and boots
> Linux subsequently. Or Windows.
> >
> > Strictly speaking, the flag is not read either by Windows nor by
> Linux. It is read by the tiny assembler program that lives in the MBR.
>

Too many threads to keep track of. Personal life is hectic.

On 26/08/2021 23:40, philo wrote:
> On 8/26/21 9:14 AM, David Brooks wrote:
>> On 26/08/2021 13:07, philo wrote:
[....]
>> Really? I don't see your response to him saying ....
>>
>> "If you place on the Master Boot Record (the MBR) a generic boot code
>> (typically, an MsDOS or Windows boot), it will search for the
>> partition marked active and boot it. And that partition contains Grub
>> and boots Linux subsequently. Or Windows.
>>  >
>>  > Strictly speaking, the flag is not read either by Windows nor by
>> Linux. It is read by the tiny assembler program that lives in the MBR.
>
> Too many threads to keep track of. Personal life is hectic.

No worries! :-D

I trust you and yours remain Covid free.

D.

All ok here.
Hope all is ok with you.

Never knew I was going to be this busy in retirement.

On 27/08/2021 00:05, philo wrote:
> All ok here.
> Hope all is ok with you.

Yes, no more trauma since my wife had her heart attack last year!

> Never knew I was going to be this busy in retirement.

Life is what you make it! Enjoy each and every day as if it is your
last! :-D