This is for Xamarin 8.10.11 (Build 8) for MacOS, Community Edition.

I recently returned to Xamarin development and opened a mobile project that I had worked on about a month ago. However both the Xamarin.iOS and Xamarin.Android projects have a yellow warning triangle beside them saying that the appropriate tool chain is not installed.

Both are installed.

If I download the latest DMG and request to install, it says there's nothing to be done (and indicates that both iOS and Android components are already installed).

Any thoughts on what else I can try?

The Show Details in the About dialog is missing all the relevant components (a colleague sent me their listing from a correctly working installation).

CodePudding user response：

So, eventually I figured it out.

The problem is that mobile development in Visual Studio is added as an extension. And for no reason I can fathom, all the Mobile Development extensions had been disabled.

I have no idea how that happened, but re-enabling them made the problem go away.