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

Note: A version of this answer, which uses macOS to create the USB flash drive OS X El Capitan installer, can be found here.

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.

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

   

2. Install all downloads except El Capitan 10.11. If you wish, the installed downloads can be uninstalled from the Windows Control Panel after use.

3. Use a 7-Zip File Manager application window to extract the OS X Install ESD folder and the InstallAssistant.icns 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
   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
   OS X Install ESD	Open	Folder
   BaseSystem.dmg	Open	Mac Disk Image File
   OS X Base System	Open	Folder
   Install OS X El Capitan.app	Open	Folder
   Contents	Open	Folder
   Resources	Open	Folder
   InstallAssistant.icns	Copy To…‡	Apple Icon Image File

   ‡The destination should be your Downloads folder.

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

4. Insert a 16 GB or larger flash drive into an USB port. If prompted, you do not need to initialize the flash drive.

5. 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.

   • Right click on the USB flash drive icon in the treeview pane, then select “Restore with Disk Image”. In the “Restore Disk Image to Drive” popup , choose to “Open” the BaseSystem.dmg Mac file in your DownloadsOS X Install ESD folder as the Disk Image to restore, then select the OK button. Next, select Yes in the “Last Warning!” popup.

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 El Capitan”, 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. In the existing TranMac window, take the following actions.

   • Select “Tools” > “Refresh Drive List” from the pulldown menu.

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

     

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

     

     Select to copy the BaseSystem.chunklist and BaseSystem.dmg files in your DownloadsOS X Install ESD 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 M:SystemInstallation folder on the USB flash drive labeled Install El Capitan, 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 Packages folder in your DownloadsOS X Install ESD 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 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.

References