Failed to Create macOS Installer on Mac/Terminal/OCLP (Error & Fix)

A macOS bootable USB installer offers various benefits to Mac users. For example, it allows you to perform a fresh install of macOS, boot up an unbootable Mac, downgrade macOS, and install macOS on multiple computers without downloading the installer each time.

While it's easy to create a bootable USB installer for macOS, you may encounter errors or get stuck in the process. This article aims to help you resolve all sorts of issues you could experience when making a boot disk for macOS.

Since you're likely creating the bootable installer from Terminal or OpenCore Legacy Patcher, we'll cover the known issues relevant to them.

💡One solution for all: Use an install disk maker for macOS

The fastest solution to all problems that prevent you from creating a bootable USB installer on Mac is to use a reliable disk creator like iBoysoft DiskGeeker.

It keeps a library of installers for macOS High Sierra and later versions, allowing you to make a macOS bootable drive from DMG files in the app. This avoids the risk of downloading corrupted installers online and wasting time on complex command lines.

For macOS Sierra and earlier systems, you can download the required Mac OS DMG file and upload it to the app to quickly make a boot disk.

Follow the steps below if you're unable to create a macOS bootable USB in Terminal or OCLP:

Step 1: Install iBoysoft DiskGeeker.

Step 2: Open the bootable USB tool, then select your USB drive from the left side and click Create boot disk. After that, click Continue to acknowledge that the process will erase your drive.

Step 3: Choose the Mac OS version you want to create an install disk with.

If you'd like a bootable USB for macOS Sequoia/Sonoma/Ventura/Monterey/Big Sur/Catalina/Mojave/High Sierra, select the macOS you want and click Create boot disk.

If you'd like a bootable USB for macOS Sierra/OS X El Capitan/OS X Yosemite/OS X Mavericks/OS X Mountain Lion/OS X Lion or earlier, click Create boot disk > Browse images, then upload the DMG file you downloaded earlier.

Step 4: Wait for the macOS bootable installer to be created.

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Issue 1: This version of xxx cannot be installed on this computer

"This version of xxx cannot be installed on this computer" will pop up when the system detects an incompatible Mac OS version. For instance, when you decompress the OS X El Capitan DMG file and adding it to the Applications folder.

The solution is to use a Mac that's qualified to run the OS you want to install, an install disk creator, or go through the steps in Issue 2.

Issue 2: Bad CPU type in executable

"sudo: unable to execute /Applications/Install OS X El Capitan.app/Contents/Resources/createinstallmedia: Bad CPU type in executable" is an error you may face when creating a boot disk for a system version that's incompatible with your Mac in Terminal. In the example, the user is trying to make a bootable drive for OS X 10.11 El Capitan on an M1 Mac.

To fix it, you can use a bootable USB tool like iBoysoft DiskGeeker, which enables you to make a bootable USB on any Mac in 5 clicks.

Or, extract the InstallESD.dmg file from the installation file and then create the install disk with it. To do this, download the wanted Mac OS DMG file and open it.

If you see an app installer, e.g., Install OS X Mavericks.app, right-click on it and choose "Show Package Contents". Then open the Contents folder, locate the InstallESD.dmg file inside the SharedSupport folder, and move the DMG file to the desktop.

If you see a pkg file, take the following steps instead:

After the DMG file is ready, you can create a bootable USB disk for the incompatible OS with the steps below:

The steps above should have fixed the message "Bad CPU type in executable." Share them with others!

Issue 3: sudo: /Applications/Install macOS Mojave.app/Contents/Resources/createinstallmedia: command not found

"createinstallmedia: command not found" is also a common error many Mac users may encounter. It's usually caused by incorrect command syntax, an installer location issue, etc. Continue reading the article below to fix it:

How to Fix Createinstallmedia: Command Not Found

Issue 4: zsh: killed sudo --volume /Volumes/MyVolume

Another problem regarding Terminal when creating a bootable macOS installer is "zsh: killed sudo --volume /Volumes/volume_name." This means that the command was forcefully terminated by the system. To fix the error, you can resign createinstallmedia binary.

Issue 5: /Applications/Install macOS High Sierra.app does not appear to be a valid OS installer application

If you don't have a full installer, you'll receive this error as a reminder. The easiest way to check if you have the full installer is to view the size of the macOS installer file. For instance, if it's only 19MB, it's obviously not a full installer.

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Issue 6: Untitled is not a valid volume mount point

The drive name of your USB can also cause issues. If Terminal says "Untitled is not a valid volume mount point," where Untitled is the name, try to rename the USB or reformat the physical disk with GUID partition map and Mac OS Extended (Journaled) as the format.

Another thing is to ensure the Terminal command is correctly typed. Pay special attention to the dashes, as they are all double dashes.

Issue 7: APFS disks may not be used as bootable install media

If your USB drive is formatted in APFS, Terminal won't accept it as a bootable install media. Therefore, you must reformat it:

Issue 8: An error occurred erasing the disk

After typing Y to continue, Terminal will start to erase the disk, preparing it before copying files to it. This process may fail with the error "An error occurred erasing the disk." Typically, you'll also receive the disk error number, which doesn't provide much information, such as:

The solution is simple. You just need to ensure your USB drive isn't currently used by another process or it doesn't share a name with the physical disk or another volume. Try these tips to eliminate the issue and rerun the command again to make a boot disk.

Issue 9: The erased disk did not mount

If your USB won't mount after being erased in Terminal, try exiting Terminal, ejecting the drive, and reconnecting it to your Mac. Then check if you can create the install disk. If not, reformat the external drive with Mac OS Extended (Journaled) in Disk Utility.

Issue 10: Stuck at Copying installer files to disk

With the USB disk prepared, Terminal will start to copy the necessary files to it. If the process hangs for a long time without progress, consider quitting it and retrying with a faster USB disk. Otherwise, wait longer.

Issue 11: The copy of the installer app failed

If Terminal prompts the error "The copy of the installer app failed," you can close the Terminal window and rerun the Terminal command. If the issue persists, you can change to a different USB.

Issue 12: Copying the macOS RecoveryOS

Terminal can also hang when copying the macOS RecoveryOS. If it happens, try reformatting the USB in Disk Utility first by following the steps we outlined in Issue 7, and then create the bootable USB again.

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Issue 13: Terminal stuck on Making disk bootable

After the necessary files are copied, the createinstallmedia utility will make the USB drive bootable. However, it may be unbearably slow and seems to be stuck on "Making disk bootable" in Terminal. In this case, you can either let the drive run all night or disable Spotlight indexing on the installer.

If you don't mind waiting, you can prevent your Mac from sleeping by changing sleep settings and letting the createinstallmedia process work overnight. It will eventually finish if the USB doesn't have issues.

If you want to see effects instantly, do these instead:

Then it should start to work.

Issue 14: zsh: bus errorsudo--volume/Volumes/macOS

There's also the possibility that you may receive the error "zsh: bus error sudo  --volume /Volumes/volume_name" after erasing the disk successfully. This error happens when Terminal doesn't have full disk access. To resolve it, you need to open System Preferences/Settings > Privacy & Security > Full Disk Access, then enable full disk access for Terminal.

Issue 15: Couldnt mount dmg /Volumes/ Install OS X Yosemite/Install OS X Yosemite.app/Contents/SharedSupport/InstallESD.dmg (error code 112)Mount of outer dmg failed.

This error indicates mounting issues with the InstallESD.dmg file. To mount it, you can delete the current installer and download a new one. If it still doesn't work, try another qualified USB.

Issue 16: The bless of the installer disk failed

"The bless of the installer disk failed" is a message that appears for different reasons. Here are the common ones:

Warning: Failed to copy product icon to volume icon path
Making disk bootable...
IA app name cookie write failed
The bless of the installer disk failed.

Couldn't extract BaseSystem to path: /Volumes/Install macOS Ventura/BaseSystem
The bless of the installer disk failed.

Failed to write IAPhysicalMedia cookie to disk
Error Domain=NSCocoaErrorDomain Code=513 "You don't have permission to save the file “.IAPhysicalMedia” in the folder “Install macOS Sonoma”." UserInfo={NSFilePath=/Volumes/Install macOS Sonoma/.IAPhysicalMedia, NSUserStringVariant=Folder, NSUnderlyingError=0x7fe41ffc31e0 {Error Domain=NSPOSIXErrorDomain Code=1 "Operation not permitted"}}
The bless of the installer disk failed.

Error Failed to create macOS installer. The bless of the installer disk failed.

Failed to patch BaseSystem. Error: Error Domain=com.apple.ParallelCompression Code=1 "Error 0xdd00d800
Invalid patch: /Volumes/Install macOS Monterey/.TempDir/basesystem_patches/x86_64BaseSystem.dmg" UserInfo={NSLocalizedDescription=Error 0xdd00d800
Invalid patch: /Volumes/Install macOS Monterey/.TempDir/basesystem_patches/x86_64BaseSystem.dmg}
The bless of the installer disk failed.

Apart from employing a bootable USB maker to work around the issue, you can also try the following fixes:

Fix 1: Grant Terminal full disk access

To dismiss the error "The bless of the installer disk failed," you can grant Terminal full disk access in Safe Mode.

Fix 2: Give OpenCore Legacy Patcher full disk access

If the problem arises when creating a bootable USB installer for macOS on OCLP, you must provide full disk access to both OpenCore Legacy Patcher and Terminal:

On macOS Ventura and later:

On macOS Monterey and earlier:

Fix 3: Directly connect to the USB

If your USB is connected to the Mac through a hub, try removing the hub and connecting it directly to your Mac. This can avoid potential issues caused by the adapter.

Fix 4: Update OCLP

If the version of OpenCore Legacy Patcher isn't the newest on your Mac, update it. This can install the new patches and bug fixes, which may allow you to create the bootable USB without issues.

Fix 5: Use a different USB

If you still can't create the bootable USB installer on Mac, it's best to try another USB or any other type of storage device. Many users ended up using a different drive after exhausting the basic troubleshooting tips.

These are all the problems that may render you unable to create a bootable USB installer on Mac and the respective solutions. If you find this guide helpful, share it to help us reach more people!