I too have the "Finding Nemo" problem
I have been looking into it and on boot nemo is not starting or is not staying running. You can go to menu-system tools-system monitor-processes and nemo is not there. By clicking on the files icon all you are doing is starting nemo up and then nemo takes over the desktop and all is well. You can also go to terminal and just type 'nemo' to start the process.
I tried forcing nemo to start by adding it to the auto start menu (menu-preferances-startup applications) and nemo does start on boot then but no Desktop icons!
So nemo files starts but it does not run the desktop still. 9M of RAM instead of 16M...
So the problem is that nemo is unable to start normally on boot due to perhaps multiple reasons.
In my case I have another computer that works fine to compare the two. I think I have found it. The good computer does not have nautilus installed and the bad computer, for some reason, does... In the system auto run (File system-etc-xdg-autostart) there are two files that will control the desktop! 'nautilus-autostart.desktop' and 'nemo-autostart.desktop'... I was playing with it and on one boot nautilus came up on the desk top!
So on boot both files are trying to control the Desktop and they are probably conflicting and shutting each other down. Thus the system boots with nobody controlling the desktop and thus no icons.
It is a bit confusing since both nemo and nautilus call themselves "Files" so it is not obvious you have two masters trying to run the show. So I am going to unistall nautilus and see if that fixes it. I just wanted to write all this before I forget what I did. But note that the Desktop handler is designed to fail off incase something goes wrong just so you don't have a dead computer or no boot issue. There may very well be other things that can shutdown nemo on boot too.
Yes that fixed it all. I removed nautilus and now the icons and all boot perfectly fine. Note that I could have probably removed nemo and then nautilus whould be the desktop controller.
So be sure you don't have nautilus and nemo or any other file and destop handelers trying to run at the same time. Otherwise, they all crash on bootup. This was not a Cinnamon or nemo problem at all but it did take some hunting to find the conflict. I hope this helps others too.
FAST SOLUTION - Do not have nautilus and nemo both installed. They will conflict and crash eash other on bootup and the Desktop icons will not come up on boot.