Endless spinner when trying to update Xcode in App Store

Here's what I had to do

• Upgrade OS X to the latest
  • This stopped the eternal spinner - instead the spinner showed for a second, then nothing happened
  • In the past, updating the App Store itself helped
• Go to the Updates tab and click UPDATE ALL
  • App Store asked me for my credentials then ran all upgrades, including Xcode

You might have to update your macOS version. Each Xcode version has a minimum macOS version requirement to work. You can find out if your current version of macOS supports the version of Xcode you want to install here: Xcode 7.0 - 10.x (since Free On-Device Development)

In my case the infinite loading spinner for the Xcode update was appearing because Xcode 9.4.1 isn't supported on the macOS El Capitan. I updated to the latest version of macOS and I managed to update Xcode.

I've done an Update All and XCode still shows an Update button. I'm on El Capitan and XCode version 8.x. I know v9.x of XCode is out but I don't know if it's available for El Capitan. I presume so since otherwise I wouldn't see the Update button, but clicking it just make the spinner run forever and it never updates