As an expert Photoshop user I am meticulous about my processes and I do not expect to lose work. Today I have lost the same job, not once, but twice, before I figured out what was causing the issue. Let me share this “feature” with you before it costs you hours of labor as well.
In Photoshop CC2015, as well as CS6, the dialog box for converting a file from one colorspace to another has a line at the bottom named “Flatten Image to Preserve Appearance”. No matter what well-meaning goals Adobe had for including this box, and defaulting it to checked, the results of doing a conversion of a multilayer file with this box checked can be catastrophic. All text layers are lost as text, all layers are lost as layers, and the resulting converted file is a flattened, one layer image. Unless you notice this change before saving the file, then you have a major data-loss situation
So, if you value your layers, and all the work they represent, uncheck this box before converting. And from now on keep one eye on the bottom of this window, rather than converting without checking these options, for fear that this option may once again have become active, and ready to lose your layers and your work!
C. David Tobie 2015