To get the latest features and maintain the security, stability, compatibility, and performance of your Mac, it's important to keep your software up to date. Apple recommends that you always use the latest macOS that is compatible with your Mac.

It was acting up so decided a re-install was the best way to go. Followed the instructions and all went well until it it restarted. Message says” OS X could not be installed on your computer”, “No packages were eligible for install. Contact the software manufacturer for assistance. “Quite the installer restart your computer and try. Unibeast 6.2.0 - installed USB drive makes it into the installer and shows '13 minutes' at beginning. About 5 seconds later, the subject text appears along with 'No eligible packages found.' Re-downloaded a fresh copy of 'Install OS X El Capitan' from the App Store, re-ran Unibeast 6.2.0 on an. Aug 24, 2021 No packages were eligible for install. Contact the software manufacturer for assistance. Quit the installed to restart your computer and try again. However, if the model Mac is too new to allow the installation for El Capitan, then message given below will occur when trying to create the Install OS X El Capitan application.

Learn how to upgrade to macOS Big Sur, the latest version of macOS.

For example, if your Mac came with macOS Big Sur, it will not accept installation of macOS Catalina or earlier. If a macOS can't be used on your Mac, the App Store or installer will let you know. For example, it might say that it's not compatible with this device or is too old to be opened on this version of macOS.

Check compatibility

The version of macOS that came with your Mac is the earliest version it can use. For example, if your Mac came with macOS Big Sur, it will not accept installation of macOS Catalina or earlier.

If a macOS can't be used on your Mac, the App Store or installer will let you know. For example, it might say that it's not compatible with this device or is too old to be opened on this version of macOS. To confirm compatibility before downloading, check the minimum hardware requirements:

• macOS Catalina 10.15 hardware requirements
• macOS Mojave 10.14 hardware requirements
• macOS High Sierra 10.13 hardware requirements
• macOS Sierra 10.12 hardware requirements
• OS X El Capitan 10.11 hardware requirements
• OS X Yosemite 10.10 hardware requirements

Download macOS using Safari on your Mac

Safari uses these links to find the old installers in the App Store. After downloading from the App Store, the installer opens automatically.

• macOS Catalina 10.15 can upgrade Mojave, High Sierra, Sierra, El Capitan, Yosemite, Mavericks
• macOS Mojave 10.14 can upgrade High Sierra, Sierra, El Capitan, Yosemite, Mavericks, Mountain Lion
• macOS High Sierra 10.13 can upgrade Sierra, El Capitan, Yosemite, Mavericks, Mountain Lion

Safari downloads the following older installers as a disk image named InstallOS.dmg or InstallMacOSX.dmg. Open the disk image, then open the .pkg installer inside the disk image. It installs an app named Install [Version Name]. Open that app from your Applications folder to begin installing the operating system.

• macOS Sierra 10.12 can upgrade El Capitan, Yosemite, Mavericks, Mountain Lion, or Lion
• OS X El Capitan 10.11 can upgrade Yosemite, Mavericks, Mountain Lion, Lion, or Snow Leopard
• OS X Yosemite 10.10can upgrade Mavericks, Mountain Lion, Lion, or Snow Leopard

Scenario

Requirements

No Packages Eligible For Install Mac Software

1. You have a 'OS X El Capitan.dmg' downloaded. (look for them in torrent.)
   
2. You have a USB drive (USB flash drive) of at least 8 GB of capacity.
   
3. All this process will happen in a OS X environment. (No Windows please.)

Happy path

1. Create an install boot drive using the USB drive and the 'OS X El Capitan.dmg'.
   
2. Boot to recovery mode in the USB drive and wipe the hard drive (ALL DATA IN HARD DRIVE WILL BE LOST, DO BACKUP!!!)
   
3. Install 'OS X El Capitan' and have a beer!

No Packages Were Eligible For Install Mac

Step 1

Mac Install Package From Terminal

1. Double click on 'OS X El Capitan.dmg' to mount this in 'Finder'. Once mount and open, it should show a name like this 'OS X El Capitan'. Copy this to your 'Documents' folder (Command + C and Command + V, or simply grab the icon and drop it in the 'Documents').
   
2. Insert the USB drive to your computer and rename it like 'INSTALL'.
   
3. Open the terminal and do this command:
   
   
   sudo Documents/OS X El Capitan.app/Contents/Resources/createinstallmedia --volume /Volumes/INSTALL --applicationpath Documents/OS X El Capitan.app
   
4. This command will ask you for your password in order to proceed. It will ask you to confirm with 'Y' for the actions that will happen in the USB drive. Once it start it should take from 15 to 30 minutes or until it finishes coping all installation files to the USB drive and making it able to boot.

Step 2

1. Restart your computer and once you hear the sound that is starting press and keep press for a while 'Option (Alt)' key until it shows a menu for select different drives. Select the one that says something like 'OS X 10.11 install drive', and click in the below arrow.
   
2. Wait until it boots up a screen of different options. Now click on the top bar on the screen that says 'Utilities', and then 'Disk Utility...'. Once open this menu, select the first 'Internal' drive (at the left), and then click on 'Erase' and on the confirmation dialog enter in the highlighted input name 'Macintosh' and then click 'Erase'. Wait until it finish doing this process. Now go to the top bar in the screen and click on 'Disk Utility' and the 'Quit Disk Utility'.
   
3. Now it should take you to the same screen when it boot up.

Step 3

1. We are ready to install but this step is the most critical one because of different errors that can happen so lets do it in way that whatever error happen we can keep trying to install.
   
2. Click on the top bar on the screen that says 'Utilities', and then 'Terminal ...'. Once the terminal is open do this command:
   installer -verbose -pkg /Volumes/Mac OS X Install DVD/Packages/OSInstall.mpkg -target /Volumes/Macintosh
   
3. The installation happens in text mode, so be patient until it finishes. At this time 2 types of error might happen:
   A. 'This copy of the Install OS X El Capitan application can't be verified. It may have been corrupted or tampered with during downloading.'
   B. 'OS X could not be installed on your computer. No package were eligible for install. Contact the software manufacturer for assistance. Quit the installer to restart your computer and try again. Restart'
   Both errors have the same solution and is very easy (and very crazy). So whenever one of this errors happens the installation stops. So we need to change the date of the computer to a year when 'OS X El Capitan' were released (don't ask me why), just type something like this:
   date 101407002015
   or date 101407002016
   after that type command
   date
   to check that the date is in 2015 or in the second case 2016.
   and then try again the installer command in step 2 in the terminal (installer -verbose etc...) and wait until the installation finishes (if the hard drive is not a SSD it will take some time, just wait until no more ### symbols).
   
4. Now click on the top bar on the screen on the apple symbol and restart the computer. Once you hear the sound that is starting DISCONNECT THE USB DRIVE and have your beer in your hand to configure your fresh Mac or iMac.