Hi ! Yesterday, I experienced a very strange behaviour of my macbook air 2013. Suddenly, when I changed spaces, the motion was very slow. The same happened to launchpad and mission control. I tried several options : resetting the permissions, smc and cleaning the caches. Nothing of those really resolved the problem. After some googling, I found an answer to my problem: I had to download quartdebug software from the Apple developper site. Here i started the app and enabled quartz debug. Then i quit again and everything worked fine again. Did anybody already have the same problem ? I wonder what could have happened ????