macos – How do I create El Capitan installer on a Catalina (or post-El Capitan) put in Mac to be used on USB boot installer?

I’ve observed that these directions now not work as anticipated when utilizing the present InstallMacOSX.dmg file, which may be downloaded from both the Apple web site “How you can obtain macOS” or the Apple web site “How you can create a bootable installer for macOS“. These directions may go as anticipated, in case you are utilizing an older saved model of this file. At finest, these directions are only a hack and Apple has each proper to vary the InstallMacOSX.dmg file to forestall the specified outcomes.

Be aware: On 1/31/2021, M. Justin reported this reply nonetheless works for Yosemite.

I’ve posted two different solutions to this query.

  • The primary different reply includes utilizing a digital machine. This reply is should much less of a hack, as a result of Apple explicitly inserted code into the El Capitan installer to bypass the checking of the mannequin when executed in a “VMware Fusion Participant” digital machine. So, Apple evidently intends for customers of newer mannequin Intel Macs to make use of this new reply to retrieve the Set up OS X El Capitan software. Nonetheless, I would love know from Apple why they thought such a posh process is critical.

  • The second different reply includes utilizing an older Mac able to operating Snow Leopard (OS X 10.6).

Under is my unique reply.

Be aware: This reply was tailored from Klanomath’s reply to a barely totally different query.

Be aware: A model of this reply, which makes use of a Home windows to create the USB flash drive OS X El Capitan installer, may be discovered right here.

There’s a hyperlink on the Apple web site “How you can obtain macOS” that may obtain a file that can be utilized to create the Set up OS X El Capitan software. Nonetheless, if the mannequin Mac is just too new to permit the set up for El Capitan, then message given beneath will happen when attempting to create the Set up OS X El Capitan software.

This model of OS X 10.11 can’t be put in on this pc.

If you’re attempting to create a USB set up flash drive of use on one other Mac pc, then you may nonetheless use the downloaded file to create this installer. The directions are given beneath.

This technique was verified through the use of the next configurations.

  • Catalina on a MacBook Professional 2017 touchbar to be used on iMac 2009 24”.
  • Mojave on a Mac mini 2018 to be used in a VirtualBox digital machine on a iMac 2013 21.5″.
  • Catalina on a iMac 2013 21.5″ to be used in a VirtualBox digital machine on the identical Mac.

The next steps can be utilized to create a USB installer for El Capitan.

  1. When you have not already downloaded then InstallMacOSX.dmg file for El Capitan, then use directions on the Apple web site “How you can obtain macOS” to obtain this file.

  2. Use the Disk Utility to erase a 16 GB or bigger flash drive. If the Disk Utility window has a View pulldown menu, ensure that Present All Gadgets is chosen. Spotlight the flash drive, then click on on the Erase button. Use the setting proven within the picture beneath.

    Subsequent, click on on the Erase button. When completed erasing, click on on the Finished button.

  3. Use the Finder applicaition to open InstallMacOSX.dmg.

  4. Enter the instructions given beneath. A folder named El Capitan shall be created within the /tmp folder to carry short-term information.

    Be aware: The simplest option to enter the instructions is to repeat from this doc and paste within the Terminal window.

    rm -rf /tmp/El Capitan
    pkgutil --expand /Volumes/Set up OS X/InstallMacOSX.pkg /tmp/El Capitan
    diskutil eject Set up OS X
    cd /tmp/El Capitan
    hdiutil connect InstallMacOSX.pkg/InstallESD.dmg  -noverify -nobrowse -mountpoint /Volumes/esd
    sudo asr restore -source /Volumes/esd/BaseSystem.dmg -target /Volumes/MyVolume -noprompt -noverify -erase

    After coming into the final command given above, you might get a message just like the one given beneath.

    asr: Could not personalize quantity /Volumes/OS X Base System

    Some variations of macOS will produce this message whereas different variations don’t. I believe that is an deadly message as a result of an exit standing of 1 was returned.

    Inspection has decided that the a part of the command that failed is unimportant.

    Subsequently, I used to be capable of ignore this error. Nonetheless, the error will also be averted by making use of the next steps given within the part beneath titled Different to Utilizing the asr Command.

  5. To complete creating the bootable USB flash drive El Capitan installer, enter the instructions given beneath.

    diskutil rename OS X Base System Set up El Capitan
    rm /Volumes/Set up El Capitan/System/Set up/Packages
    cp -rp /Volumes/esd/Packages /Volumes/Set up El Capitan/System/Set up
    cp -rp /Volumes/esd/BaseSystem.chunklist /Volumes/Set up El Capitan/
    cp -rp /Volumes/esd/BaseSystem.dmg /Volumes/Set up El Capitan/
    hdiutil detach /Volumes/esd
    sudo bless --folder /Volumes/Set up El Capitan/System/Library/CoreServices --label Set up El Capitan
    cp /Volumes/Set up El Capitan/Set up OS X El /Volumes/Set up El Capitan/.VolumeIcon.icns
    cd "$HOME"
    rm -r /tmp/El Capitan
    diskutil eject Set up El Capitan
  6. Take away the flash drive. You’re carried out.

Different to Utilizing the asr Command

The command given beneath might generate a error message and/or hold relying on the model of macOS and maybe the mannequin Mac you might be utilizing.

sudo asr restore -source /Volumes/esd/BaseSystem.dmg -target /Volumes/MyVolume -noprompt -noverify -erase


You possibly can keep away from coming into the above command by following the steps given beneath.

  1. If the amount on the USB flash drive is now not labeled MyVolume, then use the Disk Utility to erase the flash drive. Spotlight the flash drive, then click on on the Erase button. Use the setting proven within the picture beneath.

    Subsequent, click on on the Erase button. When completed erasing, click on on the Finished button.

  2. Enter the next command to create a sparse flash drive picture.

    hdiutil create -type SPARSE -size 10g -layout MBRSPUD -fs HFS+J -volname MyImage -attach /tmp/El Capitan/MyImage


  3. Mainly, you need to restore to quantity MyImage from the hidden file BaseSystem.dmg. The hidden file BaseSystem.dmg is proven within the Finder window picture proven beneath. The drive OS X Set up ESD may be discovered within the hidden quantity Volumes within the root folder.

    There are numerous methods to view hidden information. These methods depend upon the model of OS X or macOS you might be utilizing. You’ll have to go looking the online for a means that works for you.

    Spotlight the MyImage quantity proven within the Disk Utility primary window. Click on on the Restore button, then the Picture button. Choose the BaseSystem.dmg file, as proven beneath. Subsequent, click on on the Restore button.

    After a profitable restore, you must see the picture proven beneath. You possibly can click on on the Finished button and give up the Disk Utility.

    Additionally, you must get the next popup.

  4. Enter the next instructions to clone to the flash drive.

    Be aware: The dd command takes a very long time to finish. See this reply to trace the progress of the dd command. The bytes to be transferred is roughly 10 GB.

    getdsk() { native "x=$(diskutil information "$2" | grep A part of Entire)"; eval $1'="/dev/r${x##* }"'; }
    getdsk DSK1 OS X Base System
    getdsk DSK2 MyVolume
    diskutil unmountdisk $DSK1
    diskutil unmountdisk $DSK2
    sudo dd if=$DSK1 of=$DSK2 bs=1m
    diskutil eject $DSK1
    diskutil unmountdisk $DSK2
    diskutil mountdisk $DSK2


    Be aware: For the reason that unique shall be instantly ejected and finally deleted, I didn’t trouble to make use of the hfs.util command to vary the UUID of the clone.

Now you can proceed with the remainder of the steps.


How do I make a bootable USB flash drive on a Mac?
What’s one of the simplest ways to generate a Yosemite or Mavericks Set up USB flash drive?
Set up El Capitan with VirtualBox on OS X

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