Windows 8 EFI issue

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I am trying to install windows 8 on laptop with Raid 0 (stripe) as second system and have following error:

Windows can't be installed on drive 0 partition 6 (show details)

Details says: Windows cannot be installed to this disk. The selected disk has an MBR partition table. On EFI systems, windows can only be installed to GPT disks.

I am able to format partition but it doesn't help. Google says EFI and GPT is related to itanium based processors, which is not my case.

Any help would be appreciated.

st78

Posted 2012-10-26T19:54:16.360

Reputation: 213

If you have a UEFI BIOS then you should be using GPT paritions. – Ramhound – 2012-10-26T19:59:13.007

I'd like to point out that RAID 0 performance increases have been proven to be mostly negligible. I don't want to turn this into a debate about RAID 0, but you might want to look up some benchmarks and consider whether doubling your risk is worth the measured performance increases. If you're just playing around it obviously makes no difference, but I wouldn't store family photos on those drives. – Tanner Faulkner – 2012-10-26T20:12:20.237

Answers

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Like the message says, if you're booting via UEFI (which is a replacement for BIOS), Win8 requires your disk be formatted using a GUID Partition Table (GPT) boot sector.

Win7 did not support GPT on PC/BIOS, though it does support booting via GPT from EFI, as noted here.

You'll either need to reformat the drive as GPT, or you may be able to check your EFI settings and boot in a legacy BIOS mode (which would allow you to use the existing MBR disk).

As for EFI and GPT being Itanium based, that's not strictly true. Both EFI and GPT are newer standards (one for low level system communication, the other for disk partitioning layouts) that the PC industry as a whole is transitioning to.

ernie

Posted 2012-10-26T19:54:16.360

Reputation: 5 938

I am trying to create EFI partition and it is only supported on GPT disks. But you says that win7 doesn't support gpt, and it means i cannot have win7 and win8 on one disk :( – st78 – 2012-10-26T20:14:36.487

@SergeyOsypchuk Ack, my mistake . . . if you're using EFI, Win7 will boot from GPT . . . corrected my answer – ernie – 2012-10-26T20:34:52.180

thanks for help. But diskpart says 'The specified disk is not convertible'. It looks my only option is upgrade :) – st78 – 2012-10-26T21:00:49.520

@SergeyOsypchuk I'm not sure what you're doing when it says it's not convertible, but if you complete delete all the partitions and start from scratch, you should be good to go. – ernie – 2012-10-26T21:07:25.273

It's possible to convert from MBR to GPT with a few programs, such as GPT fdisk (http://www.rodsbooks.com/gdisk/). Doing so, however, will render any already-installed OS unbootable until the boot loader is updated. If the computer already has a Windows 7 installation, then it's presumably booting in BIOS mode, and so it should be possible to get Windows 8 to do the same. This will take some fiddling with firmware options or a boot-time menu to get the installer to boot in BIOS mode, though.

– Rod Smith – 2012-11-07T04:17:01.093

Asked: 2012-10-26T19:54:16.360

Viewed: 4 051 times

Active: 2012-10-26T20:33:31.493