How can I use Windows to create an OS X Yosemite USB flash drive installer from the disk image (.dmg) file downloaded from Apple?

Question

This question is NOT a duplicate of the question How can I use Windows to create an OS X El Capitan or macOS Sierra USB flash drive installer from the disk image (.dmg) file downloaded from Apple?

Here is why:

The InstallMacOSX.dmg file for Yosemite, which can be downloaded from Apple, uses the Apple Partition Map (APM). The The InstallMacOSX.dmg files for both El Capitan and Sierra, which can also be downloaded from Apple, use the GUID Partion Table instead of an APM. The Paragon Partition Manager Community Edition 64bit does not recognize APM. Therefore, instructions for creating an USB Flash drive installer for El Capitan and Sierra can not be used to create an USB Flash drive installer for Yosemite. This is why I wrote both questions and both accepted answers!

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There are many posts on the Internet where instructions are given for creating OS X USB installers by using the TransMac and other such applications on a Windows machine. Many of these posts assume one is starting with a disk image (.dmg) file made from an existing OS X USB flash drive installer.

An InstallMacOSX.dmg file for OS X Yosemite, can be downloaded from the Apple website How to download macOS. While this file can be restored to a flash drive, the result is not a working OS X Yosemite USB installer.

Note: This answer for Mavricks and this answer for El Capitan do not work for Yosemite.

How can I use Windows to create an OS X Yosemite USB flash drive installer from the InstallMacOSX.dmg file for OS X Yosemite, which can be downloaded from Apple?

Answer 1

Note: Links to instructions for other versions of OS X/macOS can found here.

Using Windows to create an USB flash drive OS X Yosemite installer requires third party software beyond just TransMac. The steps below outline one possible method for creating an USB flash drive OS X Yosemite installer using Windows and other free third party tools.

Note: Windows 11 Pro version 21H2 was used to test this answer.

1. Use Microsoft Edge (or some other web browser) to download the following installers to your Downloads folder. The file names are current as of September 22, 2022. If both 32 bit and 64 bit versions are available, the 64 bit version is given in the table.

   Product	Use	Installer	Type
   Yosemite 10.10†	Free for use on Mac computers	InstallMacOSX.dmg	Mac Disk Image
   7-Zip	Free	7z2201-x64.exe	Application
   GPT fdisk	Free	gdisk-windows-1.0.9.zip	Compressed (zipped) Folder
   dd for Windows	Free	ddrelease64.exe	Application
   TransMac	15 day free trial	tmsetup.zip	Compressed (zipped) Folder
   Paragon Partition Manager Community Edition 64bit	Free for personal and home use	Paragon-1081-FRU_WinInstallDemo_x64_17.9.1_000.exe	Application

   ^†_{If you get the message “InstallMacOSX.dmg can't be download securely”, then select “Keep”, as shown below.}

   

2. Install all downloads except “Yosemite 10.10”, “dd for Windows” and “GPT fdisk”. If you wish, the installed downloads can be uninstalled from the Windows Control Panel after use. Copy the command sgdisk64.exe from the downloaded GPT fdisk zip file to your Downloads folder.

3. Use a 7-Zip File Manager application window to extract the OS X Install ESD folder, 3.hfs file and the InstallAssistant.icns file from the InstallMacOSX.dmg Mac disk image file to your Downloads folder. From a File Explorer window, start by navigating to your Downloads folder. In this window, right click on the InstallMacOSX.dmg Mac disk image file, then select "7-Zip" > "Open archive". This should open a 7-Zip File Manager application window. In this window, right click on each file or folder in the order given in the table below, then select the corresponding action.

   File or Folder	Action	Type	Comment
   Install OS X	Open	Folder
   InstallMacOSX.pkg	Open Inside *	Package File
   InstallMacOSX.pkg	Open	Folder
   InstallESD.dmg	Open	Mac Disk Image File
   OS X Install ESD	Copy To…	Folder	See footnote ‡
   OS X Install ESD	Open	Folder
   BaseSystem.dmg	Open Inside *	Mac Disk Image File
   3.hfs	Copy To…	HFS+ volume image	See footnote ‡
   3.hfs	Open	HFS+ volume image
   OS X Base System	Open	Folder
   Install OS X Yosemite.app	Open	Folder
   Contents	Open	Folder
   Resources	Open	Folder
   InstallAssistant.icns	Copy To…	Apple Icon Image File	See footnote ‡

   ^‡_{The destination should be your Downloads folder. If this Downloads folder exists on a volume that is not NTFS formatted, then read this answer and apply the same to this answer.}

   When finished, close the 7-Zip File Manager application window.

4. Insert a 8 GB or larger flash drive into an USB port. If prompted, you do not need to initialize the flash drive.

5. 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.

   Note: See below for an alternative to this step, which does not require using GPT fdisk.

   Open an "Administrator: Windows PowerShell" window. (In other words, right click on the "Windows PowerShell" icon, then choose "Run as administrator" or "More" > "Run as administrator".) In the "Administrator: Windows PowerShell" window, take the following actions.

   • Change the current directory to be the location of your Downloads folder. If your Downloads folder is in the default location, then you can use the command given below. Otherwise, make the appropriate substitution.

     cd -d $env:userprofile\downloads
     

     Note: If necessary, the File Explorer can be used to determined the location of your Downloads folder. From the File Explorer, right click on your Downloads folder, then select Properties. When the popup titled "Downloads Properties" appears, select either the General or Location tab to view the location.

   • Enter the following to get a list of drives. Note, diskpart is an interactive command.

     diskpart
     list disk
     

   • From the values in the Disk ### and Size columns, determine the number assigned to the USB flash drive. Here the number is assumed to be 1. The following creates an empty Master Boot Record (MBR) table the USB flash drive, then exits the diskpart command. If your number is different, then make the appropriate substitution. Note, the clean command should be entered twice, as shown below.

     select disk 1
     clean
     clean
     exit
     

   • The following sets the dn variable to 1. If the number assigned to your USB flash drive is different, then make the appropriate substitution.

     $dn=1
     

   • The following commands creates a HFS type partition, which is the same size as the 3.hfs file. The ddrelease64 command zeros the first 5120 bytes of the partition. Note, the sgdisk64 command will automatically convert the drive to use the GUID Partition Table (GPT) partition style.

     .\ddrelease64 if=/dev/zero count=10 seek=40 of=\\?\Device\Harddisk$dn\Partition0
     $ns=(get-item 3.hfs).length/512
     .\sgdisk64 -a 8 -n 1:40:+$ns -t 1:af00 -i 1 "${dn}:"
     

   • The following command copies the HFS volume image in the 3.hfs file to the HFS partition on the USB flash drive.

     .\ddrelease64 if=3.hfs bs=1M of=\\?\Device\Harddisk$dn\Partition1 --progress
     

   • Close the "Administrator: Command Prompt" window.

6. Open the Paragon Partition Manager 17 CE application. Select to resize the partition with the Apple HFS volume on the USB flash drive to maximum size, as shown below. Next, select the "Change now" button. When finished, select the "Close" button.

   

   Next, select to change the volume label on this Apple HFS volume from "OS X Base System" to "Install Yosemite", as shown below. Next, select the "Change now" button. When finished, select the "Close" button.

   

   When finished, close the Paragon Partition Manager 17 CE application window.

7. 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".) In the TranMac application window, take the following actions.

   • Select "Tools" > "Settings" from the pulldown menu. In the "General" tab of the "Settings" popup, select the same copy options as shown below.

     

     Select OK when finished.

   • Navigate to root folder on the USB flash drive volume labeled Install Yosemite, as shown below.

     

   • In the listview pane, right click, then select "Copy Here", as shown below.

     

     Select to copy the OS X Install ESD\BaseSystem.chunklist and OS X Install ESD\BaseSystem.dmg files in your Downloads folder. Repeat to copy the InstallAssistant.icns file in your Downloads folder.

   • In the listview pane, right click on the InstallAssistant.icns file, then select "Rename". Change the name to .VolumeIcon.icns. When finished, the treeview and listview panes should appear as shown below.

     

   • Navigate to System/Installation folder on the USB flash drive volume labeled Install Yosemite, as shown below.

     

   • In the listview pane, right click on the Packages file, then select "Delete". When prompted, select the Yes button in the popup to confirm.

   • In the listview pane, right click, then select "Copy Here", as shown below.

     

     Select to copy the OS X Install ESD\Packages folder in your Downloads folder. (This may take a while to complete.) When finished, the treeview and listview panes should appear as shown below.

     

   • Close the TransMac window.

8. Use the File Explorer to delete the OS X Install ESD folder, 3.hfs file and InstallAssistant.icns file in your Downloads folder. If you wish, you can also delete the downloaded files. When finished, close the File Explorer window, then empty the Recycle Bin.

Alternate Step 5

This alternate step uses PowerShell and was tested using version 5.1.22000.832. If your version of PowerShell is compatible with this alternate step, then you can use this step.

Start by opening an "Administrator: Windows PowerShell" window. (In other words, right click on the "Windows PowerShell" icon, then choose "Run as administrator" or "More" > "Run as administrator".) In the "Administrator: Windows PowerShell" window, take the following actions.

• Change the current directory to be the location of your Downloads folder. If your Downloads folder is in the default location, then you can use the command given below. Otherwise, make the appropriate substitution.

  cd -d $env:userprofile\downloads
  

  Note: If necessary, the File Explorer can be used to determined the location of your Downloads folder. From the File Explorer, right click on your Downloads folder, then select Properties. When the popup titled "Downloads Properties" appears, select either the General or Location tab to view the location.

• Enter the following to get a list of drives.

  get-disk
  

• From the values in the Number and Total Size columns, determine the number assigned to the USB flash drive. Here the number is assumed to be 1. The following sets the dn variable to 1. If your number is different, then make the appropriate substitution.

  $dn=1
  

• The following insures the USB drive does not have a partition style. If prompted, enter y.

  $do=get-disk -number $dn
  if ($do.partitionstyle -ne "raw") {clear-disk -number $dn -removedata -removeoem}
  

• The following creates a GUID Partition Table (GPT) on the USB flash drive. If a Microsoft Reserve partition is created, then this partition is removed. If prompted, enter y.

  initialize-disk -number $dn -partitionstyle gpt
  $do=get-disk -number $dn
  if ($do.numberofpartitions -ne 0) {remove-partition -disknumber $dn -partitionnumber 1}
  

• The following creates a HFS type partition, which is the same size as the 3.hfs file.

  $ps=(get-item 3.hfs).length
  new-partition -disknumber $dn -Size $ps -gpttype "{48465300-0000-11aa-aa11-00306543ecac}" -alignment 4096
  

• The following command copies the HFS volume image in the 3.hfs file to the HFS partition on the USB flash drive.

  .\ddrelease64 if=3.hfs bs=1M of=\\?\Device\Harddisk$dn\Partition1 --progress
  

• Close the "Administrator: Windows PowerShell" window.

References

• sgdisk
• Other references given in this answer.