Well sometimes just deleting the dconf is not enough. When I do that the desktop starts using Marco, but in a kind of buggy state. For example whenever an application requires elevated privilege and a dialog with password shows up you cannot enter it, because the moment you push a key on the keyboard it locks up and crashes. If this happened to you too I found the solution. First delete the dconf and reboot. The open Mate Tweak, switch to compiz - it usually screws up the desktop. Then click the button to revert to compiz default. Then switch back to Marco. Then go to tty1 with Ctrl+Alt+F1 and enter marco --replace or in my case DISPLAY=:0.0 marco --replace Reboot and after that you should be able to either keep marco or switch to compiz with the Mate Tweak without issues. It took me like 2 days to figure this out. Before switching to compiz it is wise to change compiz settings with CCSM, or load a profile. If you try it later with compiz on it is prone to crashing and locking up the desktop again, so you would have to go trough all this again. Also the profile function of compiz is buggy as hell. Gave me a ton of headache. Some forum suggested installing compizconfig-backend-gconf though for wily it is stated it is a dummy package. I had to export profile from virtual 15.04 to get back settings I liked.
Yeah and when you get it working don’t ever touch it again and don’t switch back to Marco.