hi all. I've bought a new iMac 27" 5K late 2015 (bought it early december) and it has been fine all the time but suddenly a week or 3 ago he started to get problems. Finder is crashing often, preview had crashed so bad that the whole iMac crashed and needed to shut down with the power button. Usb thumbdrive that crashes all the time (dont use it anymore) And now i've had the iMac startup with a black screen with cursor in the left corner 4 times in a week. I need to shut it off with the powerbutton and start in safe boot because otherwise it just starts up again with the black screen. Im gonna call apple monday but i'm not sure what they would advise. I already did de diagnostic test (the one you do when he is starting while holding a button) and nothing was wrong. Safe boot works as supposed and i've not updated any ram or other hardware.