So it turns out I can not install Sierra because I have a Mid2009 Macbook Pro. I wanted to update to El Capitan, but it turns out its no longer available on the app store?
Any ideas, how to get El Capitan?
I am downloading it now from the App Store and it seems to be working fine. I did not go through the App Store, but used the following link:
After going to the link there is a section on how to get El Capitan from the App Store if you do not meet the system requirements for MacOS Sierra. Click on that link (pasted below) and it will open the App Store to the El Capitan App download section. Simply click on 'Get' and it will start downloading.
Edit 2019: The game has changed a lot since this QA was posted. I'd advise seeing the duplicate flagged above.
You can obtain El Capitan only if you are on a Mac which cannot run Sierra or higher.
All macOS versions, El Cap & earlier have now gone from the app store if you are on Sierra or higher.
Edit 2016: This is true for any OS except El Capitan - Apple are leaving it available so devices ineligible for Sierra can still obtain it.
You need to already have it in your Purchase History, otherwise once it's gone from the App Store, that's it, it's gone.
Your only real alternative is find a friend who can get it
... or you'd have to trust some dodgy insecure torrent etc [not at all recommended].
Yes, that previous link for 10.11.1 requires that 10.11 is already installed. You can no longer find 10.11 by searching the App Store (why, who knows?), but this page has a link for upgrading to 10.11 El Capitan from the App Store if your Mac doesn't support macOS Sierra.
After installed, then you can update to 10.11.1 with the other link posted above.
Here is the answer I got this morning from Apple support:
Here is the direct download link for El Capitan. Once you download it, you will need to click on the El Capitan Installer in your Applications folder for it to complete the installation -https://support.apple.com/kb/DL1845?viewlocale=en_US&locale=en_US