Macbook Pro 13' 2015 with OS X Yosemite on board. I've been trying to install OS X El Capitan, but always get the following message: 'This copy of the Install OS X El Capitan application can't be verified. It may have been corrupted or tampered with during downloading.' By the way this is not a date time issue, date is correct on my computer. Apple’s Mac OS X El Capitan is a free update that has further simplified the OS X experience by featuring the upgraded performance, security, and convenience. With this twelfth main release of OS X after Yosemite and Mavericks, the Mac-based ecosystem got further tighter than ever before.

Is your Mac up to date with the latest version of the Mac operating system? Is it using the version required by some product that you want to use with your Mac? Which versions are earlier (older) or later (newer, more recent)? To find out, learn which version is installed now.

If your macOS isn't up to date, you may be able to update to a later version.

Which macOS version is installed?

From the Apple menu  in the corner of your screen, choose About This Mac. You should see the macOS name, such as macOS Big Sur, followed by its version number. If you need to know the build number as well, click the version number to see it.

How To Update From El Capitan To Catalina

Which macOS version is the latest?

These are all Mac operating systems, starting with the most recent. When a major new macOS is released, it gets a new name, such as macOS Big Sur. As updates that change the macOS version number become available, this article is updated to show the latest version of that macOS.

Moving From El Capitan To Catalina

If your Mac is using an earlier version of any Mac operating system, you should install the latest Apple software updates, which can include important security updates and updates for the apps that are installed by macOS, such as Safari, Books, Messages, Mail, Music, Calendar, and Photos.

Problems Going From El Capitan To Catalina