How to Restore Independent Booting for Windows Vista and Windows 7/8.x/10

Note: This articles deals with restoring independent booting for Windows Vista and Windows 7/8.x/10. If you have installed Vista or later on a system with Windows XP please refer to the following KB article: How to Move the Windows Vista or Windows 7/8.x/10 Boot Manager and Restore the Windows XP NTLDR

Problem:

A newer version of Windows was installed on a system with an older version already installed. The newly installed Windows has taken over booting both operating systems. Independent booting of each OS is not possible. Examples include:

Installing Windows 7 on a system with Windows Vista.
Installing Windows 8 on a system with Windows Vista.
Installing Windows 10 on a system with Windows 7.

The system is booting in Legacy BIOS mode (non-UEFI) and is using MBR (or EMBR) drives.

Note: This article does not cover separating multiple versions of Windows installed on a UEFI/GPT system.

Cause:

The existing Windows booting partition (could be the Windows partition or the System Reserved partition) was set Active and visible when Windows was installed. As a result, the newly installed Windows placed its booting files onto the existing Windows booting partition. For Windows 8.x/10, the \Recovery folder (WinRE) may have also been placed on the existing Windows booting partition.

For example, Windows 8 was installed on a system where Windows Vista was already installed and the Vista partition is the booting partition. The installer placed the Windows 8 bootmgr file and \Boot directory on the Vista partition. The installer also created the \Recovery folder on the Vista partition and placed WinRE in it. Booting the system results in the Windows 8 boot menu where you can select to boot either Windows Vista or Windows 8.

Solution:

Copy the newly installed Windows booting files to the new Windows partition and apply the necessary BCD file corrections.

Important: The Windows booting files must reside on a partition with a NTFS cluster size of 4K (the default size) or less. If your Windows partition has clusters larger than 4K then you will not be able to move the booting files to it. An example would be that you've formatted the new Windows partition with 8K clusters. More information can be found in this Microsoft KB article.

Note: These instructions assume that the new Windows partition is a primary partition. If Windows is installed to a logical partition, moving the booting files to the new Windows partition will most likely result in a non-booting system unless using a boot manager such as BootIt BM.

Instructions:

Reactivate BootIt BM if it was deactivated during the Windows installation.
Boot into BootIt BM. If necessary, edit the original Windows boot item entry and make sure the new Windows partition is not hidden. Be aware if the booting partition for the original Windows is its Windows partition or if it's a System Reserved partition (e.g. Windows 7 standard install). If the System Reserved partition is used it should also not be hidden.
Boot into the new Windows installation. To do this, boot into the original Windows from BootIt BM. This will bring up the new Windows Boot Manager menu. Select the new Windows option (the menu item for the newly installed Windows).
Once Windows has booted, if it's using a System Reserved partition you will need to assign that partiton a drive letter using Disk Management. If the original Windows partition is the booting partition you can skip this step.
1. Press WinKey+R (press and hold the Windows key and press R) to open the Run dialog.
2. Type diskmgmt.msc into the Open box and click the OK button. The Disk Management window will be displayed (may take several seconds to scan the drives).
3. Right-click on the System Reserved partition and select Change Drive Letter and Paths... from the pop-up menu.
  Note: If the System Reserved partition is hidden the label won't be shown (it will be blank) and the option to change the drive letter will be disabled. The partition will most likely be displayed as "100 MB Healthy (Active, Primary Partition)" (Windows 8 or later will usually have a larger size) and be located at the start of the drive, prior to the Windows partition. Go back to Step 2 and make sure the System Reserved partition is not hidden.
4. Click the Add button.
5. An available drive letter will automatically be selected. You can keep it or select a different one. Make note of the drive letter assigned. When finished, click the OK button.
Open Explorer. For Windows Vista and Windows 7, click the Start button and then on Computer. For Windows 8.x/10, press WinKey+E or click the icon on the Taskbar.
Make note of the drive letter assigned to the original Windows partition and the letter assigned to the new Windows partition. In this example, C: is the new Windows partition and D: is the original Windows (booting) partition. Note: If the booting partition is a System Reserved partition make sure to use the drive letter you assigned to it instead of the letter assigned to the original Windows partition (the booting files will be on the System Reserved partition).

Note: It's a good idea to give the partitions meaningful labels. This can help you tell them apart more easily. For example, the label for the Vista partition might be Vista and the Windows 7 partition might be Win7. This can be especially helpful when trying to tell which partition is which from the Command Prompt.
Close Explorer once you've determined the drive letter assignments.
Open an Administrator mode Command Prompt:

If using Windows Vista or Windows 7: Click on the Start button, then All Programs, then Accessories. Right-click on the Command Prompt item and select Run as administrator from the pop-up menu. If a UAC prompt is displayed, click the Yes button.

If using Windows 8.x/10: Press WinKey+X (or right-click the lower-left corner of the Desktop) and click Command Prompt (Admin) on the pop-up menu. If a UAC prompt is displayed, click the Yes button.
Windows 8.x/10 only: Disable the Windows Recovery Environment (WinRE). In most cases, disabling WinRE before moving the booting files allows it to be easily enabled afterwards and, depending on the system, skipping this step may result in a non-functional WinRE after independent booting is established. Due to the nature of WinRE and the multitude of system configurations there may be systems where WinRE requires repairs to function properly.
1. Run the following command:
  reagentc /disable
2. Verify that winre.wim now exists in the C:\Windows\System32\Recovery folder. Run:
  dir /a C:\Windows\System32\Recovery
  
  You should see winre.wim in the list of files. If the file is missing you will likely need to repair WinRE before it can be enabled.
Unload the BCD registry hive by running the following command:
reg unload HKLM\BCD00000000
Copy the bootmgr file from the original Windows (booting) partition to the new Windows partition (make sure to use the drive letters as assigned on your computer). Run the following command:
robocopy d:\ c:\ bootmgr

Note: Windows 8.x/10 partitions usually already contain the bootmgr file (no need to copy it).
Copy the Boot folder from the original Windows (booting) partition to the new Windows partition. Run the following command:
robocopy d:\Boot C:\Boot /s
The booting files have now been copied. If you wish to verify that they were copied correctly, run the following command (make sure to use the drive letter of the new Windows partition):
dir c:\ /ah

If the bootmgr file and the Boot folder show up in the list, the procedure was successful.

The next step is to use BootIt BM to set up the new Windows menu entry and modify the BCD file settings for both Windows installations.

Reboot to BootIt BM.
Add the Boot Menu entry for new Windows. Make sure to select the new Windows partition as the booting partition.
Go into Partition Work and select the original Windows partition. Click the BCD Edit button.
In the Menu section, select the new Windows entry (e.g. Windows 7) and delete it (click the Delete button). This will allow the original Windows to boot automatically from this partition. Close the BCD Edit window.
Select the new Windows partition and then click the BCD Edit button.
In the Menu section, select the original Windows entry (e.g. Microsoft Windows Vista) and delete it. This will allow the new Windows to boot automatically from this partition.
Select the Boot section. Configure the new Windows entry (e.g. Windows 7) by following the instructions under the Important BCD Settings section of the article How to Use the BCD Edit Feature of BootIt BM.
At this point, if desired and not already done, you can configure each boot item to hide the other Windows partitions.
Windows 8.x/10 only: Boot into the new Windows and reactivate the Windows Recovery Environment (WinRE).
- Start an Administrator mode Command Prompt: Press WinKey+X (or right-click the lower-left corner of the Desktop) and click Command Prompt (Admin) on the pop-up menu. If a UAC prompt is displayed, click the Yes button.
- Run the following command:
  reagentc /enable
  
  If there are any errors or issues please refer to Repairing the Windows Recovery Environment (WinRE).

The two Windows installations should now be configured to boot independently from each other. Boot into each and make sure they work properly. If you receive an error message upon booting either partition the boot sector may need to be repaired (see How to Rebuild the Boot Sector for Windows Vista and Windows 7/8.x/10).

Technical Notes:

This method can also be performed from the original Windows installation. Before beginning, boot into the new Windows installation and disable WinRE (see Step 9). Then follow the instructions as listed with the following changes: in Step 3 boot into the original Windows installation; skip Step 9.

In addition, you can also perform this procedure from the Command Prompt of the Repair/Recovery Mode when booted to the appropriate Windows installation or repair/recovery boot media. Before beginning, boot into the new Windows installation and disable WinRE (see Step 9). Then follow the instructions as listed with the following changes: in Step 3 boot to the Windows boot media you're using; skip Steps 9 & 10. Note that you will need to determine the drive letter assignments using the Command Prompt and will have to use DISKPART if it's necessary to assign a letter to the System Reserved partition.

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