My macbook crashed after an ongoing update. I get the "?" file when rebooting it. After several test i decided to reformat my SSD as it was impossible to install a new version of mac OS X on it. At this point, the SSD is crashing the reformat or erase process from diskutil. when i launched them. The system is starting to unmount the drive. Then freezing after 30 seconds approximately.
Thanks a lot for the support Paul