I built a cube under a white point light to build a material using Cycles rendering. When I finished building my material and went to bed after saving the file, the material was kind of white with grey spots.
When I opened the file this morning, the material is pink in color. Note, I have not made any changes at all to any aspect of the file, anywhere. So with it just becoming pink for no apparent reason, I have no idea how it happened or what to do to fix it.