[vadimberman]

Concerning another dead mobile OS, I never understood why Microsoft did not try to spin off or open-source their mobile effort.

In fact, the rationale for killing it seems an example of corporate waste: it had user base in double-digits in mid-size markets like the UK and a growing base in major non-North America markets. Why not let it grow outside of America?

It was also an OS ahead of its time, at least in terms of the UI. Where else can I pin a huge preconfigured icon to the main screen to quickly activate it when I'm in a rush? Where else I don't have to scroll through the endless list of tiny icons to find what I want?

[bunderbunder]

It's likely that Microsoft's mobile OS contained large modules that the company was not going to open source either for reasons of company strategy (e.g., the kernel was probably a variant of the Windows kernel) or due to licensing restrictions.

[bri3d]

Much the same as iOS exists as a fork of OSX and shares the kernel and a lot of userland frameworks, Windows Phone 8 and 10 were just forks of Windows and shared the kernel and even more of the userland. It's unlikely Microsoft would want to open-source that.

[vadimberman]

That sounds plausible but they do collaborate with the .NET open-sourcing efforts, that could be an opportunity for them to test new waters.

[HIPisTheAnswer]

Fear of litigation.

[vadimberman]

Unfortunately, very plausible. It's ridiculous how much neat stuff is buried by corporate lawyers "mitigating" a danger as probable as a meteorite strike.

[antnisp]

SCO vs Novell will be litigated till the heat death of the universe, so you can't really blame them.