Does Windows 8 allow multiboot when installing from a mounted ISO?

I just downloaded Windows 8 and am itching to install it. The installation says it will clean everything out. I assume (hope) that it only means I cannot transfer settings from my current OS and that I will be able to multiboot like any other normal OS but I'm not sure.

I'm installing by mounting the ISO since this computer doesn't have any DVD.

Does Windows 8 support multibooting? Specically together with windows 7, without any special "put in this dvd and run this command" stuff.

richardwiden

Posted 2011-09-14T06:25:40.277

Reputation: 534

If you install to a separate partition, it should be fine. I'm still waiting for it to download though, so I don't want to answer saying it'll for-sure work the way you expect it to until I get a chance to try myself. – nhinkle – 2011-09-14T06:43:00.510

"Should" and "will" are too different for me to give it a spin "now". Have to wait until I wont need to work I guess :) – richardwiden – 2011-09-14T07:30:07.237

installing W8 now, will let you know soon :) – roman m – 2011-09-14T07:34:51.430

Are you installing from inside windows7? :) (heres to hoping) – richardwiden – 2011-09-14T07:39:44.587

YES. Was able to get the ISO to run from W7 by using PowerISO instead of MagicISO ... more to come – roman m – 2011-09-14T08:05:20.297

wow, that was fun :) i hoped W8 would ask me to select a partition to install it on, but it just went ahead and used my C drive ... I have to say, W8 looks pretty cool, too bad I'd have to reinstall all my apps. – roman m – 2011-09-14T08:32:56.453

That's what I feared. Thanks for being my guinea pig :) Write up a real answer so I can mark it as solved ;) – richardwiden – 2011-09-14T08:38:08.200

Answers

You CAN do a multiboot install without clearing anything:

Download the ISO file from Microsoft.
Mount the ISO using Daemon Tools, Clone Drive, or similar.

(This is important. Do not use the autorun installer. The autorun installer only allows you to upgrade your existing Windows installation and will not allow you to install to a separate hard drive or partition.)

Navigate to the virtual install disk and go to the folder called sources.
Run setup.exe and proceed as if installing Windows Vista or Windows 7.

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References:

LifeH2O

Posted 2011-09-14T06:25:40.277

Reputation: 1 073

UPDATE:

Yes, Windows 8 supports dual boot, but you have to install it on another partition from bootable media (such as DVD or USB drive).
Do NOT install Windows 8 from inside your OS by mounting the ISO, it will install over your primary partition WITHOUT giving you any other option (and without explicitly telling you what's going to happen).

UPDATE 2:

Windows 8 kept my Windows 7 install in (Windows.old). I'll try to revert back to it tonight as per this article. I'll report the results once I try this.

ORIGINAL:

I first wanted to install Windows 8 on a virtual machine, but I was unable to due to a lack of VT support by my processor (E4400). Then I've decided to install it on a separate partition, so I can dual-boot. I've mounted the ISO with MagicISO, but it kept crashing on me, this problem was solved by using PowerISO.

Once I mounted the ISO and fired it up, I clicked through a simple wizard, hoping that when the install files get dumped in the temp directory and computer restarts, the install will ask me to pick a partition.

Was I wrong on that one; the Windows 8 install went ahead and used my primary partition for Windows 8 install (not a big deal since I keep all my data on a separate partition).

@Journeyman Geek mentioned Advanced Partitioning option, but I didn't see it when I ran the setup.

I hope this helps.

roman m

Posted 2011-09-14T06:25:40.277

Reputation: 1 011

I had to read it twice and still can't believe it! Does this fantastic thing really overwrite the data without warning? – maaartinus – 2011-09-14T10:02:21.673

@maartinus: read my update – roman m – 2011-09-14T10:27:31.877

Better, but still: Any program must never ever destroy user's data (unless explicitly told to), otherwise it's just... – maaartinus – 2011-09-14T11:22:01.107

It says it will "clear everything" which is what got me to ask her in the first place. It even gives you a "choice" with one option "Clear everything" – richardwiden – 2011-09-14T17:09:55.057

@Richard: while it says "Clear Everything" i would assume it would ask WHERE to clear it from. Just saying. – roman m – 2011-09-14T17:21:56.867

I know, but those kinda things you cant ask of a developer preview where they probably spent most off the time making sure developers could start making apps and what-not. I can guarantee you that the full version will be 100% UAC annoying á la microsoft :) – richardwiden – 2011-09-14T17:24:28.397

Yup. Just point GRUB to the Windows 8 partition, and it wakes up like a little baby.

So BCDedit works. But I haven't gotten EasyBCD to work for some reason.

surfasb

Posted 2011-09-14T06:25:40.277

Reputation: 21 453

2Not everyone uses GRUB as their bootload. Can you expand your answer to include some more info on how multiboot might work in this scenario? – nhinkle – 2011-09-14T06:42:26.187

Oh oops. It looks like the same bootloader. I'll have to verify. – surfasb – 2011-09-14T07:34:17.373