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

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