Chosen Solution

Good afternoon, @tdunc15 - I hope you are great brother ! I have a new adventure.. I am trying to make a bootable Flash Drive with macOS High Sierra, but there is two issues that it is happening and are the nexts: a). The computer where I wish to install it supposedly is an unsupported machine (But I’ve have found on internet, that even this it could be installed, by the way). The specs of my Computer is: iMac 21.5 Inches. (Late 2009) System installed: OS X Yosemite ( Version 10.10.5 ) Processor: 3.6 GHz Intel Core Duo Memory: 4 GB 1067 MHz DDR3 Hard Drive: 500 GB Graphic Card: NVIDIA GeForce 9400 256 MB b). ’ Through the Terminal ( On my Computer ) I was trying to make the bootable Flash Drive with macOS High Sierra, but the process fails . I don’t know why, because I’ve done all the steps to create it. I have a 8GB Flash Drive [ Already Formatted by Mac OS Extended (Journaled) ]. Also, I’ve Downloaded the Software from the App Store. The next message Shows Up on the Terminal while I am trying to do it: Last login: Sat May 12 18:04:25 on ttys000 DAVIDs-iMac:~ davidson $ sudo /Applications/Install\ macOS\ High\ Sierra.app/Contents/Resources/createinstallmedia –volume /Volumes/macOS\ High\ Sierra\ (Bootable\ Drive) –applicationpath /Applications/Install\ macOS\ High\ Sierra.app Ready to start. To continue we need to erase the volume at /Volumes/macOS High Sierra (Bootable Drive). If you wish to continue type (Y) then press return: Y Erasing Disk: 0%… 10%… 20%… 30%…100%… Copying installer files to disk… Copy complete. Making disk bootable… Couldn’t mount dmg /Volumes/Install macOS High Sierra/Install macOS High Sierra.app/Contents/SharedSupport/BaseSystem.dmg (error code 110)Mount of BaseSystem failed. Done. DAVIDs-iMac:~ davidson$ Additionally, I am showing some images that maybe could help you to identify any information you may ask: • Format and Capacity of the Flash Drive.

• An image that shows the how looks inside when I open to see the Content on the Flash Drive after the process failed. Also, an image that shows how looks the icon of the Flash Drive on the Desktop.

• Information about the Wifi specs.

Thank you so much in advance !!

  1. Make sure you actually quit Disk Utility and all other Finder windows relevant to what you are doing.
  2. Instead of sudo /Applications/Install\ macOS\ High\ Sierra.app/Contents/Resources/createinstallmedia –volume /Volumes/macOS\ High\ Sierra\ (Bootable\ Drive) –applicationpath /Applications/Install\ macOS\ High\ Sierra.app, break this out into 2 separate commands a) first “sudo su” b) then without “sudo”, the rest of the command. Note: when you format the drive you intend to make a bootable installer, call it “Untitled”. OS X createinstallmedia will change the name later. So the command would look like /Applications/Install\ macOS\ High\ Sierra.app/Contents/Resources/createinstallmedia –volume /Volumes/Untitled –applicationpath /Applications/Install\ macOS\ High\ Sierra.app

Try with another USB flash drive with more capacity (16GB or more).

I am getting a different error here ““(error code 112)Mount of outer dmg failed.”” can any one suggest me what am i missing or doing wrong here. sudo /Applications/Install\ OS\ X\ El\ Capitan.app/Contents/Resources/createinstallmedia –volume /Volumes/ElCapInstaller –applicationpath /Applications/Install\ OS\ X\ El\ Capitan.app Password: Ready to start. To continue we need to erase the disk at /Volumes/ElCapInstaller. If you wish to continue type (Y) then press return: y Erasing Disk: 0%… 10%… 20%… 30%…100%… Copying installer files to disk… Copy complete. Making disk bootable… Couldn’t mount dmg /Volumes/Install OS X El Capitan/Install OS X El Capitan.app/Contents/SharedSupport/InstallESD.dmg (error code 112)Mount of outer dmg failed. Done.

I still get this error: 2020-02-01 20:20:53.831 createinstallmedia[7457:102835] *** Terminating app due to uncaught exception ‘NSInternalInconsistencyException’, reason: ‘Couldn’t posix_spawn: error 35’ *** First throw call stack: ( 0 CoreFoundation 0x00007fff3c98a8ab __exceptionPreprocess + 250 1 libobjc.A.dylib 0x00007fff72c44805 objc_exception_throw + 48 2 Foundation 0x00007fff3f056db5 -[NSConcreteTask launchWithDictionary:error:] + 5014 3 Foundation 0x00007fff3f0805d5 +[NSTask launchedTaskWithLaunchPath:arguments:] + 153 4 createinstallmedia 0x0000000101f30968 createinstallmedia + 6504 5 libdyld.dylib 0x00007fff73fb27fd start + 1 ) libc++abi.dylib: terminating with uncaught exception of type NSException Using a MBP 2017 with Catalina to create a boot installer on a SSD for a late 2009 iMac. Any ideas on how to install macOS Sierra on the 2009 iMac? No solutions are working..