Ionide F# not working in VSCode, no debug messages, not in Running Extensions

Question

I used Ionide F# a lot in the past for the amazing code completion in F# scripts. I didn't use it in a while and it doesn't work at all. I checked the debug output on level DEBUG or INFO and I only get:

[16:00:00 INFO ] .Net runtime specified
[16:00:00 INFO ] finding FSAC for
    runtime: NET
    mono: mono
    dotnet: null

Ionide doesn't show up in Running Extensions, and there's also no more other debug output. So it seems the extension crashes, but Log(Extension Host) only shows the activation of the service, not that it crashed or any other errors:

[2018-11-19 16:00:00.507] [exthost] [info] ExtensionService#_doActivateExtension Ionide.Ionide-fsharp {"startup":false,"activationEvent":"onLanguage:fsharp"}
[2018-11-19 16:00:00.507] [exthost] [info] ExtensionService#loadCommonJSModule C:\Users\mcu3si\.vscode\extensions\ionide.ionide-fsharp-3.30.0\fsharp

I'm using F# 4.5 on Windows with .NET 4.7.2. VSCode is version 1.29.1 and Ionide is version 3.30.0.

Answer 1

I found the answer and forgot to post it back in the day:

You need to have dotnet installed (that is .NET core). IMHO it should show an error message, but in case it still doesn't, that's the reason why.