EasyBCD Fails to Correctly Setup Dual Boot

#1
I installed Windows 8.1, on a GPT disk in UEFI mode (so three partitions in total, with 160 GB unpartitioned at the end).

I then installed Windows 7 SP1 on the empty space after the 8.1 partition.

All has been working fine and i was (able to dual boot into each OS using iReboot) [Note that the Windows Boot Manager menu was the black and white, not blue one if it makes a difference?]

I later used EaseUS Partition Master *on a different drive* but in same machine to change the size of a partition. For some reason this seems to have broken my dual boot. When I say broken, i mean Windows 8.1 is fine, but when try to boot into the Windows 7 OS, i get a black screen, for every.

I have used EasyBCD to delete the dual-boot BCD and re-create it, but to no avail.

Can anyone hazard a guess as to what the problem is and how i can restore my dual-boot setup?

I am running an intel z77 chipset with core i5 (i.e. recent machine). Secure Boot is switch off [because it is a really sh1t idea, introduced due to Microsoft to kerb the take up of non-Windows OS]. The disk is a Crucial M4 256 GB, it is completely error free and no other issues other than the above.

PS: A warning to others: UEFI is VERY flaky with Windows I feel, both in my testing at home and work. For resilience definitely go with MBR, the benefits UEFI bring do not outweigh the negatives).
 
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mqudsi

Mostly Harmless
Staff member
#2
We have the same opinion here, UEFI in the Windows world is simply not ready (though much of the blame really lies with the manufactures of such buggy UEFI firmware and failed implementations of the spec). Windows Vista+ can load from 2TB+ GPT disks just fine even in BIOS mode (so long as you have an MBR-accessible (even via MBR sync) boot partition on there somewhere).

In EasyBCD turn on "verbose boot mode" for the Windows 7 OS and see what happens (under advanced options). Also, not clear on where/when you're seeing that black screen - does Windows 7 begin to load at any point?

You said you resized - double-check your partition alignment.
 

Terry60

Knows where his towel is.
Staff member
#3
Windows 8.1 installs into 4 partitions in a UEFI GPT (W7 into 3, though 2 are shared in common in a 7/8 dual boot)
One of the shared is invisible even to Disk Management but shows up in a Diskpart command prompt.
My UEFI GPT 7/8.1 dual-boot isn't at all flaky so far (All new h/w since new year).
The only way I could see that partition management on one HDD could break the boot on another would be if the boot files weren't where you thought them to be, but afaik, that's a scenario that would only happen with an MBR boot.
(W7 tries hard on an MBR boot to create a "System Reserved" boot partition unless you configure the system at setup to prevent it. If you let it install to empty space, it will subdivide that space into two. You can prevent that by pre-formatting the space as one partition and that stops setup from creating the boot partition in that space. However it will make a last-ditch attempt to thwart you by looking round on other HDDs for an active partition. If it finds any, it will place the boot files in the highest priority example. In this way you can end up by unknowingly booting from a completely different HDD.
Under UEFI GPT, it doesn't matter if you pre-format the space, W7/8 will reconfigure it into the EFI System Partition and the invisible "System Reserved" partition regardless (W8 adds a recovery partition too), so I can't see how anything you do/did on another HDD can be responsible.)
Does Diskpart show 5 partitions on your GPT disk ?
 

mqudsi

Mostly Harmless
Staff member
#4
Terry, I was just going to ask what the 4th partition was - didn't realize Windows 8 stuck the recovery wizard on its own partition. Thanks for that info :smile:
 
#5
Thanks both for your replies.

Windows 8.1 installs into 4 partitions in a UEFI GPT (W7 into 3, though 2 are shared in common in a 7/8 dual boot)
Does Diskpart show 5 partitions on your GPT disk ?

I did not installed Windows 8.1 from USB/DVD, I installed it using SCCM. Therefore there are 4 parts in total: 300mb Recovery Part, 500 MB EFI part, Win 8.1 and Win 7.

Turn on "verbose boot mode" for the Windows 7 OS and see what happens (under advanced options). Also, not clear on where/when you're seeing that black screen - does Windows 7 begin to load at any point?

You said you resized - double-check your partition alignment.
Windows 7 does not seem to start booting, it goes straight from the boot menu to choosing Win 7 to black screen, so it is clearly something up with the bcd/boot settings preventing W7 from starting to boot.

How do I check partition alignment, and what should it be set to???
 
#6
Sorry, correction, one partition is hidden in diskmgmt??

Partition 1 - Recovery - 300 MB - 1024 KB
Partition 2 - System - 500 MB - 301 MB [FAT32]
Partition 3 - Reserved - 128 MB - 801 MB
Partition 4 - Primary - 78 GB - 929 MB
Partition 5 - Primary - 158 GB - 79 GB
 

Terry60

Knows where his towel is.
Staff member
#7
Yes, seems crazy to me too, but I mentioned that even DM can't see one of the five.
Since they are all there, then I can't see how anything you did to a different HDD can possibly have affected your boot.
Are you 100% certain that you didn't accidentally modify something on the GPT disk with your partition manager ?