Upgrade Windows 7 to 10 with Yosemite on the same drive

[Keny Hu]

I have a dual boot system with Yosemite and Win 7 installed on the same drive as following:

 

/dev/disk0
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:      GUID_partition_scheme                        *1.0 TB     disk0
   1:                        EFI EFI                     209.7 MB   disk0s1
   2:                  Apple_HFS Laurasia                499.6 GB   disk0s2
   3:                 Apple_Boot Recovery HD             650.0 MB   disk0s3
   4:       Microsoft Basic Data Gondwana                499.8 GB   disk0s4

disk0s1 and dis0s4 apparently belong to Windows. And I am using Chameleon as the boot loader.

 

I want to upgrade Windows 7 to 10 but I wonder if I can do it directly or will it potentially destroy my Mac partition?

 

Anyone with similar configurations has already succeeded in upgrading?

 

 

[JahStories]

you should just reinstall your boot loader after the update!

[fusion71au]

@Keny Hu,

 

Yes, you can upgrade to Windows 10 directly without destroying your Mac partition.

 

The main problem with upgrade installs is that they require the Windows bootloader to be in charge of booting to be successful (the first reboot after installation files are written to the HD will fail otherwise).  The upgrade also overwrites the bootsector so it will remove third party bootloaders/bootmanagers like Chameleon/Clover from the MBR.

 

My solution is to leave the Windows 7 bootloader in charge on the MBR before upgrading to Windows 10.  You can still chainload to Clover or Chameleon (on the PBR) when you want to boot OSX:

 

 

1.  Open an elevated command prompt in Windows and run the following commands to make the Windows partition active:

diskpart
list disk
select disk # (where # is the disk where Windows is installed)
list partition
select partition * (where * is the partition number of your Windows installation)
active
exit

2.  Install EasyBCD to restore the Windows 7 bootloader code to the MBR and setup a boot manager entry for OSX (chainloads to Chameleon).

  a.  Run EasyBCD and click the "BCD Deployment" button on the left.  Under "MBR Configuration Option", select "Install the Windows Vista/7 bootloader to the MBR" and click "Write MBR"

 

  b.  Click the "Add New Entry" button on the left and select the Mac tab under "Operating Systems".  Under "mode", select MBR and click the "Add Entry" button.

 

  c.  Click "Edit Boot Menu" and rename the entry to whatever you want eg "OSX" or "Chameleon".  For the purposes of upgrading to Windows 10, set the Windows entry as the default.

 

  d.  Finally, click "Save Settings", and exit EasyBCD.  To boot into OSX, restart the computer and at the Windows Boot Manager, select OSX/Chameleon to chainload Chameleon and boot into OSX....

3.  Download the Windows 10 iso with the Media Creation Tool.  Mount the iso and run the setup.exe from inside your activated Windows 7 whilst connected to the internet to get the free upgrade .