My mid-2010 iMac, running High Sierra, crashed and won’t recover. It won’t boot unless in recovery mode, but I can do very little in that mode. I ran First Aid and got an all clear on both the SSD & HDD, but the HDD part of my fusion drive reads as full, when it was only just over half full before, so there’s definitely something wrong there. The HDD is also described as “uncounted”. I cannot erase the drive using Disk Utility, that option is greyed out. It won’t recognize my Time Machine backup to restore from there. It won’t find a disk for me to reinstall the OS. I don’t have a boot disk/drive. Ummm...help?!!