El Capitan disk has an embbed security certificate that has expired in 2016. Just change your system date, let's say to, install El Capitan, then change the date back to today. MacBook Pro 15' Unibody Mid 2009.
Compared to versions of Mac OS X released after El Capitan, such as Sierra, El Capitan generally is not faster. Mac computers dating from 2012 and later will generally run more smoothly when upgraded from El Capitan, per Apple's optimizations in Sierra and later. On the other hand, Macs from 2008 to 2010 may run faster with El Capitan.
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.
Check compatibility
Sep 30, 2015 This lasted ages. I watched 'Pointless' on TV then was just going to stop the install but looked at the install logs and it was still adding to the log. Then it started to reboot and all was well. So this last second on the progress indicator took over 40 minutes. El Capitan appears to be working fine but has not yet had a thorough test. If you cannot install Office 365, you could contact Apple Official Support to change the version of your MAC. By the way, this tag is for Exchange online server side, if you have more question about Office 365 client, you could post new question with office-itpro tag。. 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.
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.
Ios El Capitan Will Not Install
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:
Os X El Capitan Will Not Install
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
El Capitan Won't Install
Download macOS using Safari on your Mac
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
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.
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