Disk utility in El Capitan installer does not have security option

Due to issues related to secure erase of flash memory, they disabled the feature. I don't know if it will be restored.

I ran into a related problem with the new disk utility on my fusion drive. I booted from usb El Capitan, used terminal to delete coreStorage, then went to disk utilities and clicked on my SSD to fix my fusion drive (it would do that in previous versions of disk utility). Disk utility version 15 does not do that!, so I was left with a broken fusion drive. I then restarted and booted into internet recovery (alt command r) and was able to access an older version of disk utility (Lion) which fixed my fusion drive and also offered security options for erase. I then rebooted into the El Capitan installer and was able to do a clean install. I would point out that SSD do not need security options for erase, one pass is complete erasure and multiple erasure's only shortens the life of the drive. Rotational HDD's are a different story.

Therefore, if you only have a SSD, you should be fine. If on the other hand, you have a rotational HHD, then your options are to boot into Yosemite

and do your erase from there or, boot into internet recovery (lion thru Yosemite, (don't know about previous versions)) and erase from there, then boot to your El Capitan installer. Apple just made it much harder to do a clean install, especially on a fusion drive.

Best of Luck: Tom

Your welcome, glad I share some of the things I learned the hard way.

Tom

This happened to me last night. Trying to prep my iMac 5K for shipment but encountered problem with disk utilities on El Capitan. First, there was no security option when erasing Mac HD. Then when erasing, it ran into some error and the HD disappeared altogether. It wouldn't even show up on available drive list when I tried to reinstall OS. Called Apple support and they had me use terminal commands to delete the volume. The disk reappeared and I was able to reinstall El Capitan but when I started it up, something didn't look right. I have a 1.1TB fusion drive but Finder told me my disk is only 999GB. Looks like the SSD portion was gone. Then I found this posting. I did an internet recovery and was able to get a Yosemite version of Disk Utilities. Immediately, it told me my Fusion Drive was not formatted correctly. Once I did the fix option, I got my 1.1TB back and I was offered the old erase security options. I had to use diskutil rename command to rename the LVG from Internal Drive (somehow the repair caused that) back to Fusion Drive. After that I reinstalled Yosemite and it looked like everything was back to normal. After all that I'm avoiding disk utilities on El Capitan until a few OS updates. Thanks EVISCERATOR. It saved me a trip hauling the 5K back to Genius Bar.

Glad you got it sorted out! By the way, if your fusion drive is repaired in Yosemite disk utilities, it names it internal drive and Macintosh HD as default. When you upgrade to El Capitan it is automatically defaulted to Fusion drive. I have found that El Capitan's disk utility will erase the drive with out having to use terminal (coreStorage delete) and El Capitan does not separate the drives. Know that if you ever need to secure erase or other wise manipulate the fusion drive you can always boot into internet utilities and use the disk utility from there. Apple changed disk utilities for El Capitan to prevent unnecessary wear and tear on the SSD drives because multiple erasure is not necessary and greatly shortens their life.

SSD drives should never be zeroed.

Happy fusion driving: Tom