Hi!
I also have this problem. The computer freezes and the keyboard and trackpad becomes completely unresponsive. I can feel that the “click” in the trackpad stops working. The only solution is to restart the computer by holding down the power button. The problem always comes when I use Safari and when there is some kind of embedded video on the web page.
I have a brand new Macbook Pro Retina 13¨, 8 GB RAM, 250GB SSD, Early 2015. The graphic card is Intel Iris Graphics 6100. The problem persists in Mac OS 10.11.4, but was solved by downgrading to 10.10.5 (More about that below).
When the problem occurred the first time I reacted immediately. I am a long time Mac user and have never encountered this kind of freeze in any of my computers. I started to search in forum for others who had this kind of problem. I immediately found hundreds of hits around 2013, when a similar problem was affecting the Macbook pro 13¨. That time Apple released a software update. But I also discovered this thread and some other discussions regarding the 2015 years’ model.
So my first question was if it was a hardware or software related problem. The last time the problem was reported back in 2013, Apple solved the problem with a software update. If the problem was related with the 2015 years’ model of Macbook pro, that would support the theory that it is in fact a software problem. The fact that not all Macbooks are affected would on the other hand support the idea that it Is a hardware problem affecting only a small number of computers.
I started to follow every recommended fix for the problem: I reset NVRAM and SMC, I checked the permissions, reformatted the ssd and reinstalled El Capitan. Nothing worked. The problem came back in a couple of days. I also tried every setting for the trackpad, and for the graphic card and for Safari (i.e. shutting of the use of web GL).
Then I read about people that was complaining about the 10.11.4 upgrade. They said that they didn’t have this problem before they upgraded to 10.11.4. That was the preinstalled version on my computer. I then googled and found out that my computer model had been shipped with Yosemite. I then decided to reformat the ssd and downgrade to 10.10.5 (the last version of Yosemite). Once I installed Yosemite 10.11.5 my problems was gone. The computer just worked day out and day in. One very important conclusion was that the problem is software related. There’s nothing wrong with the hardware. When I use 10.11.5 the computer never freezes.
So after a couple of weeks I started wondering what would happen if I clicked on the button “Upgrade to El Capitan”? I had a working computer, and maybe if I upgraded now the problem would not comeback (this Is what you could call magical thinking ;-) So I upgraded to El Capitan. In two days the problem was back.
So now I have a working computer running 10.10.5 and I have no freezes. Actually no problems at all. But I cannot upgrade to El Capitan. So am stock with Yosemite until Apple solves the problem. What I have read 10.11.5 don’t solve the problem. I hope Apple will fix it in a future update.
So what is my conclusion about the problem? I think it is a software problem (but probably connected to drivers/hardware of a certain model) that Apple needs to fix. I have reported the problem to Apples support channel twice, but have not heard back from them.