Active1 month ago

My MBA 2012 with OS X 10.9.4 Mavericks won't boot anymore - it simply freezes after the initial jingle. I already tried resetting NVRAM and SMC, but to no avail. I don't have any time machine backups.

However, I still have a disc image of Mavericks sitting on an external hard drive, a USB stick and access to a notebook with Windows 7.

The Windows 7 USB/DVD Download tool is a great tool. It creates a DVD or USB device, loaded with Windows 7 setup files, for you in seconds. It creates a DVD or USB device, loaded with Windows 7 setup files, for you in seconds. Download and install the Windows USB/DVD Download tool. Open the Windows USB/DVD Download tool. When prompted, browse to your.iso file, select it, and click Next. When asked to select the media type for your backup, make sure your flash drive is plugged in, and then choose USB device.

I haven't yet found any tutorial on how to create a bootable USB drive on Windows in order to reinstall OS X on my beloved Macbook Air.

Any help would be greatly appreciated!

kinarikinari

8 Answers

According to the first answer here, https://superuser.com/questions/383235/create-a-bootable-usb-drive-from-a-dmg-file-on-windows, there's a tool with a free trial called TransMac that can do it. Just make sure the USB drive is formatted with GPT and not MBR.

What might be easier, however, is that that model has support for Internet Recovery. If you boot holding Command-R and you have a WiFi connection, it can actually boot into recovery mode without a recovery partition on a drive (or even without a working drive).

Having said that, your description of a crash right after the boot chime could signify a more serious hardware problem and you may not be able to boot anything. If you boot holding the option key down, the startup disk selection screen should appear. If it crashes anyways, you may be looking at a hardware problem.

Community♦

Michael D. M. DrydenMichael D. M. Dryden

I know this question is old but it is still valid. I was never able to write a Mac installer image to my Flash Drive and have it bootable, unless I did it on a Mac. Using Michael D. M. Dryden's Link, I was able to use the Diskpart command to clean and prep a GPT partition on a flash drive for an OSX Mavericks install image.

I used TransMac on Windows 7 to restore the image file I had to the Flash Drive, it created a bootable Mac image on my flash drive. Someone had reported that the method for using DISKPART did not work, but I have done this twice and it works remarkably well, and it's the only method I could find to create a Mac-Bootable Flash. I've been trying to post this to confirm that it works for some time, I just hope it helps someone else, because it is a very easy solution.

Here are the Diskpart commands used to prep the Flash Drive, just to have them here in case my Link does not work:

(Find the disk number)

Disk x is now the selected disk.

DiskPart succeeded in cleaning the disk.

DiskPart successfully converted the selected disk to GPT format.

Note: I use 'Rufus' for all other USB writing and formatting for Windows systems, it's a great app, but I had previously tried to format the drive as GPT using that, as a Fat32 partition. When I tried to inject the image, Transmac told me that the drive was 'write protected'. So basically, the USB drive cannot have any high level formatting, the Windows system should detect the drive as 'not formatted' for this to work, which it will if prepped right with Diskpart.

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XweAponXXweAponX

I was able to do this with Power ISO on Windows but it cost me $29.99

-- I created an ISO from the original install DVD and then went to tools => Create Bootable USB...Selected the OSX imageSelected the USB drive to create the bootable image onSelected RAW mode

I popped it in my Desklamp iMac (DVD Drive busted from toddlers -- majority of OS was trashed by 5yo) and boom ready to install.

JoshJosh

I had this problem with a friend computer, it was an old iMac and I'll tell you it is not going to be easy.
The first thing you have to do is make sure what model you have (the year when your computer has been released) then check on the official apple website to see what is the latest macOS or Mac OS X version available for you computer.
In most of the new mac computer, you can just press cmd+r while booting and the mac will automatically download everything you need to install the system, but the oldest does not have this tool.
In this case, you have to download the dmg file, that can be found on the web, for example, one websites that provides some macOS and Mac OS X is this (for El Capitan, if you need another version, I'm sorry but you have to search for it).
Here things start to get a little tricky.
First of all you have to flash the image on a USB drive, I recommend etcher, that works on everything (Mac, Linux and Windows too) it's extremely easy to use and you just need to select the drive and the image and etcher will do everything by itself, plus it's free here.
When the USB drive is ready you can plug it in you mac and press alt (option) while booting, you have inserted a firmware password, it will ask you to unlock the firmware by inserting that password, else it will take you to all the bootable drives, including your USB device.
If you see the mac logo with a stop icon over it, it means that you downloaded a too new version that is not supported from your mac, else it will start.
When it start, it won't install, saying that the system can't verify the downloaded image, that's why you have to navigate on the 'utilities' menu on the top bar and open the terminal.
Now you have to choices, change the date & time, which can work, but may not.
That's basically because every image of mac has a certificate that can expire, so, if the certificate is expired you won't be able to make it work, unless you change the date (the date is different from mac version to mac version, so based on that you have to change it, usually just search for when was that version released and se the current date to that date or even one or two days later to make it work). Then try to install the system, if this does not work again, you can start the installation without verifying the image, but you should really trust the image you're using from being corrupted or modified (just to make sure the download went right, use the SHA-1 code to make the file has been downloaded right).
So, to proceed without verifying the image, from terminal, type in this command: sudo defaults write com.apple.frameworks.diskimages skip-verify true
then, start the installation. (Is possible that you won't need the sudo at the begin, in that case just remove it from the command and start from 'defaults')
Now you should be able to install macOS from a USB drive...
Just a little thing, make sure to have formatted the disk before proceeding, I would recommend to make a partition that takes the whole disk in mac Journaled format, then if you want you will be able to encrypt the disk (the installer will ask you to do that later), instead, if the disk was encrypted before, you will have to insert the encryption key of the disk to continue the installation process.
Really hope this help, I spent a lot of hours to do this on a really old iMac from 2008... and now it works!
Good luck!

Pietro De DomenicoPietro De Domenico

In my humble opinion, the easiest and a free solution for creating bootable drives is Rufus.

Jawa

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user115395user115395

I've been struggling with the same problem but this works for me:

convert the .dmg image with power iso to iso
put the iso on a usb stick (drag it into your mac hard drive and mount it)
format your usb stick with the disk utility tool. (Make sure the usb is partitioned as mac bootable then use use the image recovery and put your mounted OS X iso into the source and your usb as the location.)
restart your computer while holding down the option key

dwightk

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Windows 7 Usb Install

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