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.
According to the first answer here, -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.
Create Usb Boot Disk For Mac Os X Lion With Windows 10
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.
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.
Copy the InstallESD.dmg Mac disk image file to your Downloads folder. This file can be found in the Contents/SharedSupport folder of the "Install OS X Mavericks" application. If the volume containing this file is HFS+ formatted, then use TransMac to copy the file, otherwise use Windows Explorer. If you need to use TransMac, then open the TransMac application with Administrator privileges. (In other words, right click on the TransMac icon, then choose "Run as administrator" or "More" > "Run as administrator".)
Internally, the BaseSystem.dmg Mac disk image file contains a drive that is using the Apple Partition Map (APM), which is not well supported in a Windows environment. This step creates a GUID Partition Map on the USB flash drive instead of copying the APM from the BaseSystem.dmg file. Once the partition is created on the USB flash drive, the HFS volume image stored in the 3.hfs is copied to this partition.
In fact, there are very few ways that can be used to write DMG image file to a USB drive and have it to be bootable on a Windows computer. As far as i konw, some third party tools like Transmac, poweriso, etcher or sysgeeker's WonderISO.but none of them are free, I suggest you download the trail version and use it for 3 times without paying.
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!
For those who failed to create bootable USB with TransMac, take a look at UUByte DMG Editor. I managed to create two bootable USB from macOS Mojave and Catalina DMG file and successfully installed them on respect Mac.
I've tried many tutorials on how to create a mac bootable USB drive from Windows but none of them worked. So, I've come up with my own solution that worked fine with any DMG I've tested. Please find the details on my github page.
As far as I know, the only way to properly create a bootable Lion disc/disk is to use Disk Utility on a working Mac. However, the other option is to use a Virtualbox VM to run OS X temporarily (scroll down for that info).
What operating system do you want?If it is the OSX that was on your system you can do following easier:Restart in the RecoveryPartition, click your language, then choose Install OSX.And OSX will be installed on your system.I assume that it is Yosemite afterwards.Then decide if you want to upgrade, do it from the Appstore, or stay. If you want to have a bootable stick later on:Download DiskMakerX and make a bootable stick with it.
If the USB flash drive is not working with TransMac, it could still be a partition problem. In this case, you may need to redo the entire process. However, this time, you should follow these steps to use the Diskpart command-line utility on Windows 10 (or 11) to create the appropriate GPT partition, and then follow the above instructions.
Once you have formatted the USB flash drive with a GPT partition, you can use the instructions mentioned above to use TransMac to create a bootable media, but this time, skip steps 5 through 10 and continue on step 11.
Thought I'd share some useful information. I'd been hunting around online for a way to create a bootable USB so I could reinstall OS X Lion on my mid 2009 Macbook Pro. TransMAC is a really easy program to use, all I had to do was create the GPT partition on my USB and it worked great!
The OS X Recovery Disk Assistant lets you create OS X Recovery on an external drive that has all of the same capabilities as the built-in OS X Recovery: reinstall Lion or Mountain Lion, repair the disk using Disk Utility, restore from a Time Machine backup, or browse the web with Safari.
I have a Mac Air gifted by son. I am almost a dummy, with only very limited proficiency in mac. Son upgraded the OS to Lion free as it was allowed. It is running OK. Do I still have to spend USD 30/- to make a bootable USB stick. Is there any other method to make Boot USB key or MicroSD via USB reader for a dummy like me.
If you open App Store and click Updates, you can update your Lion installer to version 1.0.16. It replaces your copy if you allowed it to self-erase at installation. But using the InstallESD.dmg from inside this installer (SHA1 = 8ef208772f878698e9dd92b3632e25b23ffc9ca7) creates a bootable 10.7.3 (11D50) USB stick. That is cool.
Is this bootable Lion image something that you can use as an emergency repair disk by adding things like DiskWarrior and TechTools Pro (when they are lion certified)? Or is this bootable image only capable of booting and installing Lion?
To get this to work, we have to sacrifice the Mac OS X Lion Recovery partition. Then when we add the Windows and shared partition, the total will be 4 partitions. Deleting the Recovery partition was not a problem because I plan to make a bootable USB key containing the Mac OS X Mountain Lion install. Unfortunately, because the Recovery partition is a hidden partition, we cannot use Disk Utility to delete it. Instead, we will use the Terminal command line to erase and merge it with our Mac OS X partition.
Do you mean to install Mac OS X 10.8 Mountain Lion on a Mac computer which has no OS installed (basically, doing an install, not an upgrade)? If so, you can create a bootable DVD or USB key containing the Mountain Lion OS installer which you can then use to install 10.8 on a computer.
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