PSD file missing all layers & folders, black background only when opened.

I was working on a file this morning which had several layers grouped into folders, nothing fancy, some transparency. Saved it, closed PS (cs6). Windows (7) was trying to update and wanted to restart, and I do so.

I open the file again later, all of the layers have disappeared, all of the folders have disappeared, and the 'background' layer, which I'd removed, is back, completely black, locked.

The file size is still 178 MB. If I save a copy from PS, it goes down to what you'd expect a file containing essentially nothing would be, a few kb. If I max out contrast I can see a one-pixel strip of noise across the top of the artboard, and everything else stays black.

I assume the update process ruined the file somehow. Wondering if there's any way to recover/revert. The fact that the file retained its size has me hoping there's a way.