I have had no luck installing bootcamp Windows 8 or Windows 10 on my late 2015 iMac. The first time I tried with Windows 8 and got Apple support involved resulted in the iMac getting returned. Apple support completely screwed up the main partition and could not return it to its original size. My second iMac i tried to use bootcamp to install Windows 10. On both machines I got to the same spot where Windows was installing from the ISO file and got to the point where the disk partitions were all listed and I selected the one called bootcamp. When I would select it it would say Windows must be installed to a NTFS partition. When I select format, it would think for a few seconds but then display the partition list with the bootcamp name remove from the partition. When I select "next", it says we could not create a new partition or locate an existing one. On my first iMac Apple support tried to create and format the bootcamp partition with disk utility since the bootcamp utility wouldn't work. That was not at all successful. So what's the deal, no bootcamp on El Capitan? Thoughts?