Fix fusion drive partition mess from bootcamp assistant I have a self made fusion drive on a 2009 iMac using a 256gb ssd and a 3tb hard drive. After the 10.8.3 update yesterday I tried to create a bootcamp partition but unfortunately it failed after hours. I had a look at the hard drive manager and the bootcamp partition (I've set it to 303gb) was already there. After having a closer look i noticed that the partition was in the middle of a 1.7 tb partition which was now used for the fusion drive and a 800gb partition that wasn't used anymore. It looks like the bootcamp assistant failed while moving the partition around on the drive.

I started the assistant again to make him remove the partition again which I did but still left the hard drive split into two parts - the 800gb part is still unused and unusable.

Here is what diskutil cs list says:



Does anyone have a hint for me how I can merge these 800gb part into my fusion drive again?
The surefire fix is to format everything and recreate your Fusion Drive, then restore from a backup.

Hopefully someone can help us fix this another way, but my research shows that non-destructively merging content onto a live fusion drive isn't supported by Apple or another tool chain yet.