IMac OS Sierra gets black screen after login

Hi

I have an IMAC 27 inch 16gb ram 3TB with SSD with IOS Sierra 10.12.4 with bluetooth Apple standard keyboard and an Wacom Intuos Bamboo tablet as a mouse.

Yesterday i was working on my computer when the OS started to get slow.

the pointer of Bamboo tablet freezing time to time and i had to wait some seconds to moving on.

The OS seemed to have some peaks of memory or disk usage. So I resolved to reboot my computer.

I am a developer with a lot of deploiment and web server enviroment like Node, Apache, Mysql.. some times things get wrong and i have to reboot my computer.

But yesterday, after my reboot, i made my login, and then my computer gets several minutes with that colored circle (processing) and after that the screen shows me a black screen. The strange thing is that i could move my mouse, and uses all my keyboards controls like brightness, sound.. even when i pressed some keys a sound was played.

It looks like my computer works but with a “blind“ screen that cant show me the GUI interface.

So, I access my computer with ssh from my iphone and everything is ok. I could enter on terminal and navigate through files and execute all sorts of commands like LS...

My GUI was died but the terminal was not affected.

I tried SDN restart, tried to restart the default configuration with opt cmd r p tried to boot with shift (security mode) and the problem still occurs.

At terminal I see disk usage, memory usage and tasks opened.. everything is normal.

I run disk utility with recovery boot... nothing resolves this problem

I tried to reinstall MAC OS Sierra but a popup appears with "you don't have permissions to install this software, enter on apple store"

I saw /var/logs/system.log (I attached some images in this ticket)

Any clue about this problem?

Thanks!