Erasing CFast/SxS cards under OS X El Capitan

[Oliver Temmler]

If you need to erase a CFast (or SxS card) on a Mac, you typically may want to use Apple's Disk Utility.

1) Open Disk Utility - located in /Applications/Utilities/ - easier to open via Spotlight search.
2) Select the “Volume” i.e. the card you want to erase on the left side of the Utility.
3) Go to the Erase Tab (right up there with First Aid, RAID and Restore).
4) Click ‘Erase…’.
It does not matter which Format or Name is selected. The camera will always ask you to format the card again before it can be used.

That all works fine up to OS X Yosemite. Apple, however, made some changes under the hood of OS X 10.11 El Capitan, which causes Disk Utility to fail in the above task. The workaround is to find a Mac with an older OS, or to take a short trip into the Terminal.

1) Open Terminal - located in /Applications/Utilities/ - easier via Spotlight search.
2) Enter "diskutil eraseVolume HFS+ empty /Volumes/A001R00J"
- without the quotes
- replacing A001R00J with the name of your card.
3) Press Enter.

Hints: In terminal, you can just type "/Vol” and then press the TAB key to auto-complete the directory name. Same for the card name. Type “A0” and press TAB to auto complete. The command will erase the card named A001R00J and initialize it as an HFS+ volume with the name empty.

NOTE: This operation will erase all data on the card. So if there is data on the card and you still need it, make a backup before you erase it.