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Windows 7: GPT Win 8 Dual boot installation killed Win 7 MBR boot option.

02 Feb 2014   #1
BrokeIC

Windows 7 Professional x64
 
 
GPT Win 8 Dual boot installation killed Win 7 MBR boot option.

I've had Win 7 Pro on my laptop for over a year. I installed a 2nd hard drive to it recently and today I installed Windows 8 Pro on the 2nd hard drive. It's been a roller coaster of good & bad luck.

The first install went fine, until I tried to install the Windows 8.1 upgrade from the Windows store, then things went bad and I had to go into Windows 7 and eventually delete the Windows 8 volume and change it from MBR to GPT because of UEFI (no secure boot enabled thankfully). Gawd what a stretch of error messages telling me I can't install Windows 8 on the blank hard drive because it was or wasn't MBR or GPT, or the automagically made partitions weren't in the right order.

After spending over 7 hours twice in a row installing Windows 8, I finally find out that there's no boot option for Windows 7 anymore.

The only clue I have is to use a Windows 7 repair disk and use diskpart.exe and make the Win 7 drive "active" but that's a little foreign to me at this point.


My System SpecsSystem Spec
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02 Feb 2014   #2
BrokeIC

Windows 7 Professional x64
 
 

I'm looking in Computer Management / Disk Management from within Windows 8.

Disk 0: SYSTEM D: 438 MB NTFS (lengthened from 199 MB with EaseUS because Acronis 2014 thought it too small while crashing), Healthy (Active, Primary Partition); Win 7 E: 930.98 GB NTFS Healthy (Primary Partition); HP_TOOLS F: 102 MB FAT 32 Healthy (Primary Partition)

Disk 1: 300 MB Healthy (Recovery Partition) {no letter}; 100 MB Healthy (EFI System Partition) {no letter}; C: 931.00 GB NTFS Healthy (Boot, Page File, Crash Dump, Primary Partition)

And several other external disks which don't deserve mention today.
My System SpecsSystem Spec
02 Feb 2014   #3
theog

Microsoft Community Contributor Award Recipient

ME/XP/Vista/Win7
 
 

Set the UEFI/BIOS firmware to LEGACY OS boot & Secure Boot DISABLED, see if Windows 7 x64 LEGACY will boot.
My System SpecsSystem Spec
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02 Feb 2014   #4
BrokeIC

Windows 7 Professional x64
 
 

It was switched to legacy before I tried to install Windows 8, maybe installing Windows 8 switched it to UEFI? I haven't checked yet, that would require a reboot.
My System SpecsSystem Spec
02 Feb 2014   #5
theog

Microsoft Community Contributor Award Recipient

ME/XP/Vista/Win7
 
 

Quote:
Disk 1: 300 MB Healthy (Recovery Partition) {no letter}; 100 MB Healthy (EFI System Partition) {no letter}; C: 931.00 GB NTFS Healthy (Boot, Page File, Crash Dump, Primary Partition)
Windows 8 x64 UEFI, will not boot in legacy mode.

Quote:

It was switched to legacy before I tried to install Windows 8, maybe installing Windows 8 switched it?
My System SpecsSystem Spec
02 Feb 2014   #6
BrokeIC

Windows 7 Professional x64
 
 

It was in Legacy mode like I left it. I even tried a couple boots in UEFI mode and there was little difference except it was quicker to get to the Win 8 lock welcome screen, and it disconnected my external monitor, & external mouse & keyboard until I got past the lock screen, I wasn't paying close enough attention to that feature.

I did see the boot options on my first installation of Win 8 before 8.1 wiped out the entire works.

I know the boot options did work when both drives were MBR, but now with one drive being GPT, that seems to throw a monkey wrench into the dual boot scheme. It wouldn't let me install on an MBR drive a second time even after a wipe, just my luck.
My System SpecsSystem Spec
02 Feb 2014   #7
gregrocker

 

It was not necessary to reinstall Win8 to UEFI BIOS, since you could have kept Win8 UEFI and preserved your boot menu. You can still Clean Install - Windows 8 to UEFI after disabling Legacy and booting the installer as a UEFI device.

Each BIOS is slightly different but to boot both UEFI and LEgacy you need a Legacy or CSM setting Enabled or Both.

Have you tried installing EasyBCD (click Download - no Name or Email required) to Windows 8 to add Win7 to a Dual Boot menu.

Will Win7 boot by triggering its HD with the BIOS Boot Menu key? THis is actually a better way to Dual Boot separate HD OS"s, setting preferred to boot first and then using BBM key to boot the other.

If problems persist post back a screenshot from Win8 of Disk Management - Post a Screen Capture Image
My System SpecsSystem Spec
02 Feb 2014   #8
BrokeIC

Windows 7 Professional x64
 
 

I've tried a little bit of bcdedit from the command line following this articleHow to Add OS to Windows Boot Manager | eHow and it did give me back the boot menu for Windows 8/7, but I must have made a mistake because it still won't GO to Windows 7.

I think my mistakes were in Step 4 I referred to device partition=D (which is a small SYSTEM partition), and step 5 couldn't be entered correctly at all. I tried osdevice partition=D: and osdevice partition=E: but I haven't tried osdevice partition=C: yet; but is says osdevice partition=C: in the bootloader anyway for that entry.

Windows 7 shows up in msconfig under Boot, but maybe the pathway is askance.
My System SpecsSystem Spec
02 Feb 2014   #9
whs
Microsoft MVP

Vista, Windows7, Mint Mate, Zorin, Windows 8
 
 

I would disconnect the Windows 7 HDD when installing Windows 8.1 on the other HDD. Then you get no bootloader conflicts. Switch between the 2 systems with the BIOS boot sequence (F12 or ESC during boot).
My System SpecsSystem Spec
02 Feb 2014   #10
gregrocker

 

Were you going to try the steps I gave you which have worked in countless thousands of cases here?

Install EasyBCD, delete any Win7 listing that was added, then add it again. Reboot.

If that fails post back a Disk Mgmt screenshot screenshot also already requested so we can advise you better.
My System SpecsSystem Spec
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 GPT Win 8 Dual boot installation killed Win 7 MBR boot option.




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