I have upgraded to El Capitan, but I was having this problem for a while, where the desktop background doesn’t display. The folders have white letters, and the background is white, and this makes everything difficult to read. The background image doesn't change immediately, I have to log out, and log back in. I can see it has changed, on the login screen, and after I have logged in. But at some point, the screen turns white, and thus the problem.
I have turned off all the start up applications, and the problem remains.
I have looked for view options in Finder, but I cannot figure out why the desktop remains white.
I have tried the normal ways of changing desktop background, but it doesn’t work. Alternatively, I can not see it, because something is blocking it? That is a guess.
Inverting colours in the accessibility menu doesn't help, as inverted colours mean I'm looking at black on black instead of white on white.
I created a new user. The new user doesn’t have this problem, their desktop is visible.