A new version of macOS is always exciting. But it can quickly become frustrating if, instead of being presented with a brand new Mac, ready to use, you see an error message like “macOS could not be installed on your computer.” Fortunately, you can do lots of things to fix the problem, so let’s get started.

Before you try to install a new version of macOS

• This went absolutely fine and I now have a fully indepentent USB Drive which i can simple connect to the PC and the El Captain OS boots up. Case 2: I next tried to use the same bootable USB to install El Capatin on a SATA Drive. I had formated the drive for OS X Extended (Journaled) with Guided Partition Table.
• As explained here, OS X 10.11 'El Capitan' fails to install because it is too old (the technical reason being that the signing certificate is no longer valid). But you can trick the OS X installer into thinking that it is 2017 and it will happily run without any errors. How to trick the OS X installer. When the OS X installer complains that 'No packages were eligible for install' and displays this window: don't restart your Mac.

It’s essential that before you perform any major upgrade, say from Catalina to Big Sur, that you backup your Mac. One of the steps described below involves a complete reinstall of the operating system, resulting in erasing data from your drive. It’s best to do the backup using Time Machine, as you can then use Recovery Mode to restore your Mac from the backup. But if you don’t want to use Time Machine, create a bootable clone of your startup disk using a tool like SuperDuper or Carbon Copy Cloner.

Why does “macOS could not be installed on your computer” appear?

Here is what we can do: Open disk utility from the Utilities menu or from the Utilities folder. Now you need to select the disk on which you want to install Mac OS X. Select the partition tab in the Disk utility Windows. You will then see a pop up menu from which you have to choose the desired number of partitions you are looking for. If I try to install Big Sur by App Store I receive the following sentence: update not found the requested version of macos is not available. I am very disappointed about this. All server status are on, the OS has been released 11 days ago and I have no VPN or other programs running that could create problems. Obviously I have enough space in.

There are several reasons you might see this error message. Here are some of the most common.

• Your Mac doesn’t support the version of macOS you’re trying to install
• There was a problem downloading the installer
• You don’t have enough space to install a new version of macOS
• There’s a problem with the disk on your Mac
• A piece of software like a launch agent or launch daemon is interfering with the upgrade

Before you try to fix the error

Check if your Mac is compatible with the version of macOS you’re trying to install. The best way to do that is to launch the App Store app, search for the macOS version you’re trying to install, and scroll down the Compatibility section. You should see a message that says, “works on this Mac.” Alternatively, go to Apple’s website support pages and search for the minimum system requirements. You might need to reboot in Safe mode, see below, to check because if you do a normal restart, your Mac may immediately relaunch the installer.

How to fix “macOS could not be installed on your computer”

1.Restart your Mac in Safe mode

Safe mode disables startup items, launch agents, and everything else except the bare minimum macOS needs to function. Restart your Mac from the Apple menu or by holding down the power button, and press Shift until you see the Apple logo.

2. Try running the installer again while in Safe mode

If the problem were that launch agents or daemons were interfering with the upgrade, Safe mode would fix that. If it works, you should restart your Mac normally after the installation and remove any launch agents and daemons you don’t need.

The simplest way to remove launch agents is to use CleanMyMac X.

Here’s how:

1. Download, install and launch CleanMyMac X.
2. Choose Optimization from the sidebar on the left.
3. Select View all items.
4. Check the box next to Launch Agents
5. Press Run.

3. Free up space

You’ll need up to 20GB of free space on your main drive to download and install an update to macOS. If you don’t have that much free space, it’s time to clear out the junk and free up space. I’ve found that the quickest and easiest way to do that is to use a popular app CleanMyMac X by MacPaw. It can free up tons of gigabytes of space with a couple of clicks.

Install CleanMyMac X, then launch it — download free edition here.

1. Choose Smart Scan from the sidebar.
2. Press Scan.
3. When it’s finished, press Run to delete files immediately or Review Details to see what it has found.

4. Reset the NVRAM

The NVRAM on your Mac stores data even after your Mac shuts down or restarts, unlike regular RAM, which is flushed every time you restart. NVRAM persists, thanks to a small amount of power supplied by your Mac’s internal battery. Resetting NVRAM rarely has any effect, but it can do in some situations, and as it won’t do any harm, it’s worth trying. It’s quite tricky to do, so that you might need some help.

Restart your Mac while holding the Command + Option (Alt) + P + R keys and wait until you hear a startup chime. It may take a little longer than normal to restart twice, but the NVRAM will have reset once it's done.

5. Try the combo updater

If you can restart in Safe mode and quit the installer, try downloading the combo updater from Apple’s website. The combo updater contains all the files necessary to install macOS on all Macs, whereas the version downloaded from the App Store only has the files for your specific Mac. It may be that the combo updater works, where the Mac App Store version doesn’t.

6. Install in Recovery Mode

How Do You Fix No Packages Were Eligible For Install

This is the last resort if nothing else works.

1. Restart your Mac while holding Command + R until you see the Apple logo.
2. When you see the macOS Utilities window, you have two choices. You can either restore your Mac from a Time Machine backup if you have one, which will take you back to where you were before you started. Or you can Reinstall macOS.
3. Choose the option you want.
4. If you chose Reinstall macOS, wait for your Mac to restart, then go to System Preferences > Software Update and update your Mac to the latest available version.

There are a number of things you can do to fix your Mac when you see the message: “macOS could not be installed on your computer.” If the problem is that you don’t have enough space, you can use CleanMyMac X to get rid of files you don’t need. Otherwise, go through the above steps one at a time until you’re able to install a new version or update to macOS.

Scenario

Requirements

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 Os X

Step 1

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

No Packages Were Eligible For Install Os X El Capitan

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.