Installing El Capiton on an old Mac Book Pro today, I received the error:

1. Cannot Install Os X El Capitan Os
2. Cannot Install Os X El Capitan Using
3. Cannot Install Os X El Capitan Update
4. Cannot Install Os X El Capitan
5. Can't Install Mac Os X El Capitan
6. Cannot Install Os X El Capitan Mac

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X 10.11 'El Capitan' fails to install because it is too old (the technical reason being that the signing certificate is no longer valid).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 fix 'This copy of the install OS X El Capitan application can't be verified. It may have been corrupted or tampered with during downloading.

DVD DL, Mac OS X 10.11 El Capitan Full OS Install Reinstall Recovery Upgrade. Latest certificate (expires ). Please CHECK twice if your Mac model is compatible with this macOS!! If you are not 100% sure please check the pics or message me your mac model and year and I can tell for sure if would work or not! Once you’ve done that, here’s how to install, reinstall, or upgrade to El Capitan, step by step: Boot from your Recovery HD partition by restarting your Mac while holding down the Command+R keys. The OS X Utilities window appears. Select Reinstall OS X, and click Continue. The OS X El Capitan splash screen appears. Set the Name to El Capitan. Set the Format to OS X Extended (Journaled). Set the Scheme to GUID Partition Map. Click Erase to format the drive. Install OS X to the Target Drive. Exit the Disk Utility and click Install OS X. Click Show All Disks and select the drive you just formatted to install OS X on it. Finally, click Install.

OS X could not be installed on your computer

No packages were eligible for install. Contact the software manufacturer for assistance.

Quit the installer to restart your computer and try again.

I checked Apple’s support Matrix (it is a very old macbook pro) at https://support.apple.com/kb/SP728?locale=en_GB and it was listed as supported.

After lots of Googling and investigation, I discovered that the date and time were not set to current, the macbook thought it was year 2000.

You can easily reset the time and date by following the steps below:

• Click Utilities on the menu bar
• Select Terminal
• Type date
• Confirm the date is wrong
• Type date 062112422016 (example: June 21st 12:42 2016)
• Exit terminal
• Click Restart

Cannot Install Os X El Capitan Os

Once the Date and time are configured you will be able to install OS X.

Easy fix, for a ridiculous error!

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.

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

Cannot Install Os X El Capitan Using

Check compatibility

Cannot Install Os X El Capitan Update

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 may say that it's not compatible with this device or it's 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

Cannot Install Os X El Capitan

Safari uses these links to find the old installers in the App Store. After being downloaded from the App Store, the installer will open automatically.

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

Can't Install Mac Os X El Capitan

Safari will download 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 will install an app named Install [Version Name]. Open that app from your Applications folder to start installing the operating system.

Cannot Install Os X El Capitan Mac

• 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