OK Hands up I made a Dumb Mistake. Went to install Bootcamp on 2013 iMac with 1Tb Fusion Drive, got it all screwed up and deleted partitions via the windows installer and Disk Utility Now I am stuck with a system that is working but witha 200Gb Unusable Partition where Bootcamp was going to be. This space is just greyed out I cannot do anything with it in Disk Utility from the machine or from the Recovery Partition. I dont mind doing a complete wipe (I have a Time Machine Backup to restore from), I just want my entire 1Tb Fusion Drove back. This is the situation mydrive is in It will not repair or repartition from the OS or from Recovery. it is just stuck, if anyone as had similar and can talk me through getting the space back or a full reset to orginal space even it it means a reinstall I would be most grateful. I cannot add or delete partitions as all the options are greyed out.