Hi! I've recently installed Mac OS X Sierra. After installing Mac os x Sierra my hard drive had stopped being read. I've went to disc utility and tried first aid, it didn’t work. I have rebooted my computer. Went to disc utility again and tried first aid again, didn’t work. It said that my hdd is not initialized, when i went to info it says that my drive is not writable, it can’t be repaired, can’t be verified & can’t be bootable. I've also tried to run my hard drive on a windows computer, and it worked perfectly fine, the drive wasn't full and the files were all in place. I've contacted apple through feedback assistant, but I've got no reply for almost a week. Please help, I've left the pictures for you to have better understanding of the problem I have.