Atmel Studio 6, which is (ununderstandably!*) based on Visual Studio (2010?), suddenly stopped showing anything in the Solution Explorer pane.
The pane was there, it just remained empty, blank, apart from the "Properties" button (and the "Show all files" button shows up too, depending on the frontmost pane).
After some googling for a fix, it seemed hopeless; even similar bug reports at Microsoft sites on Visual Studio were answered officially with things like "let me know if after reformatting the hard drive the problem is still there". WTF??
Well, luckily turns out that at least in my case it was simply that I had changed an option: Projects and Solutions - General - Always show solution. I had unchecked that checkbox, thinking that I don't need the solution to be shown ALWAYS and that maybe the IDE would do something more flexible/intelligent. Hah. Fat chance.
SO: just check that checkbox. And migrate** to Eclipse, which is what I am trying to do right now.
**(Why migrate? Because I am fed up with Atmel Studio half-working in their different incarnations. AVR Studio 4 stopped simulating months ago and I still could not find a way to make it work - looks like it COULD be an interaction with Office and/or Visual Studio (all from Microsoft!!), but I already tried uninstalling/reinstalling all of them in different orders and nothing helps. Which might be moot since anyway installing AVR Studio 4 in a fresh VM doesn't help either. Later Studio versions don't simulate my µC, and from time to time they pull some BS like this Solution Explorer scare. So, nothing to loose, and in Eclipse at least I might be able to customize more of it, like using ccache, which in Atmel Studio was pretty problematic. Apart from Eclipse + CDT looking more standard / reusable, of course)
*(Why ununderstandably? Because the GCC toolchain, the heart and brain of the development environment, is open source and multiplatform. Why in hell tie it to a propietary, single-platform IDE like Visual Studio, when Eclipse + CDT are open source and developed/used/pushed by other manufacturers?? The only answer a friend has been able to come up with is that maybe Atmel wanted to keep something closed-source, or to avoid users jumping ship once they are in a more open platform where other µC's can be used. But the closed-source thing doesn't hold water (they could just bundle some proprietary tool with Eclipse) and the jumping-ship thing sounds like a great reason NOT to enter the Atmel environment in the first place - if your defence against competition is burying yourself in a hole, then well, you have buried yourself already :P)