IntelliJ doesn't recognize flutter plugin

Question

I wanted to try out flutter with IntelliJ, so I followed the order of https://flutter.io/setup-macos/ and everything worked out. But today, out of nowhere, it doesn't work anymore. I can run my code, but reload and hot reload is disabled. So I'd have to close and restart everything, every time, I'd like to see a change. "flutter doctor" tells me:

IntelliJ IDEA Ultimate Edition (version 2017.2.5)
✗ Flutter plugin not installed; this adds Flutter specific functionality.
• Dart plugin version 172.4155.35
• For information about installing plugins, see
  https://flutter.io/intellij-setup/#installing-the-plugins

But I looked it up, and flutter clearly was installed. I honestly sit here for 5 hours now, trying to figure it out, but I just can't find the problem. I deleted and reinstalled Flutter, Dart and IntelliJ like 4 times now, but it didn't work either.

Flutter in generall works, at least I can run the app in the terminal, so the problem got to be with IntelliJ. I also deleted the following folders:

macOS
~/Library/Application Support/IntelliJIdeaXX
~/Library/Preferences/IntelliJIdeaXX
~/Library/Caches/IntelliJIdeaXX
~/Library/Logs/IntelliJIdeaXX 

Does anyone have an idea of what I can do now?

Answer 1

It was reported several times recently. master is the development branch with some newer code. alpha dev (default) is the recommended channel, but there are currently issues with dev which are already fixed in master. dev will be updated soon and it's recommended to switch back to dev when the fixes have landed.

flutter channel master

to switch back later

flutter channel alpha

flutter channel dev