First off sort out the problem with the battery.
Next confirm whether your Mac is running 10.6 which is Snow Leopard or 10.9 which is Mavericks.
- After months of testing and development, Apple is finally letting you download and install Mac OS X 10.11 El Capitan for free from the Mac App Store. Apple initially introduced the world to OS X El Capitan during this year’s Worldwide Developer Conference (WWDC) back in June, as has become company tradition. In the months that have followed.
- 8/10 (114 votes) - Download macOS El Capitan Mac Free. The twelfth version of Mac OS X appeared in 2015. MacOS El Capitan is the successor to Yosemite with improvements to its functions and graphical performance. MacOS is the current name of the former OS X, previously known as Mac OS X.
Update Mac OS X to El Capitan (Download OS X 10.11.6) Bonus Tip: Restore lost data after El Capitan update (without backups) This page collects complete process for all old Mac OS X users to follow and upgrade their Mac into Mac El Capitan.
If it is 10.6 Snow Leopard make sure it is fully updated to 10.6.8, use the App Store for that, if it is 10.9 Mavericks make sure it is fully updated to 10.9.5. Click on the Apple top left of your screen then click on About This Mac to see info about your Mac.
Whichever OS you are actually running open Disk Utility from the Utilities folder in your Applications folder and run Verify/ First Aid on your disk to check for errors. If errors are found then you will need to boot to your Recovery Drive, this will have been installed along with Mavericks, About macOS Recovery - Apple Support then use Disk Utility from there. If you are on Snow Leopard you will need the original install DVD so you can boot from it and open Disk Utility from there. El Capitan was only ever available as a free download direct from Apple, if you are buying it or any 'recovery' DVD you are being ripped off.
To download El Capitan, read this, How to upgrade to OS X El Capitan - Apple Support scroll down to Section 4 and click on Get El Capitan.
Some other things that might be of use to you are to reset the NVRAM, reset the SMC, boot to Safe Mode. You could also try installing El Capitan in Safe Mode.
Check compatibility
You can upgrade to OS X El Capitan from OS X Snow Leopard or later on any of the following Mac models. Your Mac also needs at least 2GB of memory and 8.8GB of available storage space.
MacBook introduced in 2009 or later, plus MacBook (13-inch, Aluminum, Late 2008)
MacBook Air introduced in late 2008 or later
MacBook Pro introduced in mid 2007 or later
Mac mini introduced in early 2009 or later
iMac introduced in mid 2007 or later
Mac Pro introduced in early 2008 or later
Xserve models introduced in early 2009
MacBook Air introduced in late 2008 or later
MacBook Pro introduced in mid 2007 or later
Mac mini introduced in early 2009 or later
iMac introduced in mid 2007 or later
Mac Pro introduced in early 2008 or later
Xserve models introduced in early 2009
To find your Mac model, memory, storage space, and macOS version, choose About This Mac from the Apple menu . If your Mac isn't compatible with OS X El Capitan, the installer will let you know.
Make a backup
Before installing any upgrade, it’s a good idea to back up your Mac. Time Machine makes it simple, and other backup methods are also available. Learn how to back up your Mac.
Get connected
It takes time to download and install OS X, so make sure that you have a reliable Internet connection. If you're using a Mac notebook computer, plug it into AC power.
Download OS X El Capitan
For the strongest security and latest features, find out whether you can upgrade to macOS Catalina, the latest version of macOS.
If you still need OS X El Capitan, use this link: Download OS X El Capitan. A file named InstallMacOSX.dmg will download to your Mac.
Install the macOS installer
Double-click the downloaded file to open a window showing its contents. Then double-click the file within, named InstallMacOSX.pkg.
Follow the onscreen instructions, which will guide you through the steps necessary to install.
Begin installation
Download Mac Os X 10.11 El Capitan Or Later
After installation of the installer is complete, open the Applications folder on your Mac, then double-click the file named Install OS X El Capitan.
Click Continue and follow the onscreen instructions. You might find it easiest to begin installation in the evening so that it can complete overnight, if needed.
Allow installation to complete
Please allow installation to complete without putting your Mac to sleep or closing its lid. Your Mac might restart, show a progress bar, or show a blank screen several times as it installs both OS X and related updates to your Mac firmware.
How Do I Download Mac Os X 10.11 El Capitan
Learn more
How To Download And Get Mac Os X 10.11 El Capitan.iso
- OS X El Capitan won't install on top of a later version of macOS, but you can erase your disk first or install on another disk.
- You can use macOS Recovery to reinstall macOS.