Csdrhrt

I just finished installing Windows 10 preview, build 10130. But I wanted it to use its own system partition. Instead, it detected my other Windows installations and reconfigured the system partition that I use for those installations. I have Windows 7, and Windows 8.1 on one HDD. I wanted to install Windows 10 on a second HDD.

Is there a way to set the system partition during installation setup, to explicitly tell the installation program what physical drive and what partition I want to use as the system partition? I had created a first primary partition of 512 MB and set it as active in Diskpart. Why did it not take that primary, active partition and use it as a system partition? I also created one big extended partition and one logical partition to hold Windows 10.

This is what I wanted:

HDD0:

Windows 7 (primary, active, system)

Windows 8.1 (logical)



HDD1:

boot_win10 (primary, active, system)

Windows 10 (logical)

This is what I have:

HDD0:

Windows 7 (primary, active, system)

Windows 8.1 (logical)



HDD1:

Windows 10 (logical)

I want the HDD that holds Windows 10 to be independent of the other Windows installations. For that to work it needs its own system partition and its own bootloader and boot manager configuration. What can I do at this point without having to reinstall Windows 10? If I do reinstall, how can I make sure that the setup will use the same HDD for system partition? Is it possible?

Change the boot priority in BIOS setup so that the HDD that you want to install Windows 10 on gets first priority. Windows setup will use this HDD to configure a system partition on, with all the necessary boot files to boot the new Windows installation. You may even choose to install Windows on a different HDD, but it is the HDD that has the first priority in BIOS setup that gets the system partition configuration. The Windows setup will ignore any other system partitions you may have on a second HDD, as long as it is not the first priority HDD in BIOS setup. In case the first priority HDD already contains a valid Windows system partition with one or more Windows installations configured, the Windows setup will inspect it and only add a new boot menu entry to the existing system partition. It will not overwrite it.

This is a somewhat crippled solution, because the Windows 10 setup somehow managed to affect my existing system partition on the second HDD. This HDD was not set as the first priority HDD in BIOS setup. So Windows setup should have ignored it. It did ignore it, to the effect that it did not add a new boot menu entry to that system partition. Instead, it created a new system partition on the HDD that had the first priority in BIOS setup, as explained above. But it appears to have altered the default boot option for the boot manager on the old system partition, and changed its boot menu policy to "Legacy" instead of "Standard". It actually said "Standard" when I ran the bcdedit command in cmd, but in reality, it was set to legacy.

The "legacy" boot menu policy is the old text-mode boot menu used in Windows 7 and earlier. The "standard" policy is the new graphical boot menu used in Windows 8 and later.

To correct this, boot into one of the installed Windows versions that uses the affected system partition configuration, and run the following commands.

bcdedit /default {id}

bcdedit /set {id} bootmenupolicy legacy

bcdedit /set {id} bootmenupolicy standard

Replace the "id" with the ID number of the boot entry you want to set. This may look something like {default} or {current} or {f14fdad6-164a-11e5-b0ca-fe74f2eeab83}. To get the full list of all the boot entries, run the following command.

bcdedit /v

You will see an output that contains sections like this:

Windows Boot Loader

-------------------

identifier              {current}

device                  partition=C:

path                    Windowssystem32winload.exe

description             Windows 8.1

locale                  en-US

inherit                 {bootloadersettings}

recoverysequence        {f14fdadb-164a-11e5-b0ca-fe74f2eeab83}

integrityservices       Enable

recoveryenabled         Yes

allowedinmemorysettings 0x15000075

osdevice                partition=C:

systemroot              Windows

resumeobject            {f14fdad9-164a-11e5-b0ca-fe74f2eeab83}

nx                      OptIn

bootmenupolicy          Standard

Each one of these sections represent one operating system and the boot entry options for that system in the boot manager configuration, known as a BCD store. This is a file stored somewhere on your system partition.

The above output shows the boot entry options for the Windows 8.1 installation. The command was issued from within that system. Hence, the identifier of {current}. The command was bcdedit which gives you a standard output like that. To get a full ID, you need to use the verbose option (v) as indicated above.

I you want to make changes to a BCD store of a different system partition than the one that's used by the currently running system, you will have to point the bcdedit to it. The same commands might look something like this for a BCD file stored on a different system partition:

bcdedit /store d:bootbcd /default {id}

bcdedit /store d:bootbcd /set {id} bootmenupolicy legacy

bcdedit /store d:bootbcd /set {id} bootmenupolicy standard

I tested this with Windows 10 and Windows 8. But as far as I know the same applies to Windows 7, Windows Vista. Basically all the Windows versions that use the new bootloader model with BCD. With the exception that Windows 7 and Vista don't support the "standard" boot menu policy. The idea of setting boot priority in BIOS setup to indicate where you want the system partition to go to is even older than Windows Vista. It should work for Windows XP and Windows 2000, if not even Windows Me, 98 and 95.