My newly macbook air can't install windows 7 via boot camp even I have formatted the SSD in the window installer

Something you are leaving out probably.

You say you formatted the parition.

page 22 in the guide where you select "BOOTCAMP" and click Advanced Option and format to NTFS.

what happens then? error message?

You have OS on same (SSD) drive / you don't have another drive (internal or external) connected with OS X.

Windows won't install if it sees GPT (apple calls it GUID) present on another drive.

There are lots of 2012 MacBook Air users with Windows 7.

Odd. Did you do as the guide instructs?

http://manuals.info.apple.com/en_US/boot_camp_install-setup_10.7.pdf

Maybe you went "outside the lines" and used Disk Utility in ways to change the partitions, size, number, etc.

Using NTFS driver in OS X for instance to create a partition.

Which might mean the only way now going forward would be to restore everything back to the beginning and restore.

I'm having the same problem. Yes, I followed the instructions completely all the way through clicking Format under advanced options for the BOOTCAMP partition. It appears to format it correctly, but when I click Next, I get the message "Setup was unable to create a new system partition or locate an existing system partition."

I read in the forums that I should unplug the USB drive. I tried that and instead, get the following message:

"Windows is unable to install to the selected location. Error: 0x80300001"

I have a new Retina display running Mountain LIon and the latest of everything. I tried installing both Windows 7 Home Premium SP1 ISO and Windows 7 Pro SP1 ISO, both downloaded from Microsoft. I am booting from a 32GB USB3 drive. I used Boot Camp Assistant for everything.

I removed my old Windows XP VM from Parallels, wiping everything. The only other thing I can think of is that my MacOS is connected to Time Machine, but MacOS is not running while Windows is trying to install itself.

Any ideas? Thanks!

Disconnect everything.

the presence of another drive with Apple's GUID-GPT will screw it up. Any operating system since XP 'knows' how to look for foreign formats like GPT and GPT has a MBR protective layer to keep XP out.

Two drives with GUID, Mac boot drive and another, are death to installing Windows.

ISOs have to - sure you know by know but to be 100% - burned (do you burn to a USB flash drive?) as the slowest speed possible. With DVD burn they fail at some point otherwise.

I don't have anything else plugged in and since Windows did not finish installing, there is no wifi to get to anything else, right?

I used Boot Camp Assistant to burn the ISO onto the flash drive. The flash drive is USB3. There was no setting/option to burn it at any particular speed. Could the problem be that I need a USB2 flash drive instead?

btw, Yes, I can see everything was correctly burned onto the flash drive by Boot Camp Assistant, including the Apple stuff in Windows Support. Boot Camp Assistant did everything for me, with no options.

I must have been misled:

. The only other thing I can think of is that my MacOS is connected to Time Machine

And that is or isn't connected like you said?

GPT + EFI has rules and it would be nice if someday Apple would actually implement a scheme instead of using MBR.

Time machine is connected via wifi, which is also my router.

Since bootcamp isn't a VM like Parallels - MacOS isn't running, right?

And Windows hasn't gotten very far in its installation before it dies (right after format), so I haven't set it up for wifi. So nothing is reaching Time Machine. I guess the only reason I mentioned it was out of habit since I've used Parallels in the past.

It was indeed the USB3 flash drive. I bought a USB2, repeated everything, and it worked fine!

Thanks for your help!

Great to hear.

And the things like connected, but via wifi also make it hard for us to see what is there. And you cna of course unplug the TM drive from the router unless it is one of those new ones built-in like WD and Netgear have done.