So I had my iMac set up with two partitions. 1 - OS disk 160GB 2 - Other 500GB Please note the 'Other' partition was empty. I either didn't research that well, or read the instructions I found by googling. But I had tried to merge the two partitions. I clicked on the main drive (WD 640GB) in disk utility - Clicked on the partition tab - the chose 'other' and clicked the minus sign... Something went wrong from here. Now Disk Utility shows the main drive (WD 640GB) as 640GB. But I click on OSX - It still only shows 16GB I have lost the other 500GB. Im not sure how to get it back..