Q: SXS memory card doesn't work with El Capitan

Did you recently upgrade your OS?

Are you trying to use the Express slot on your 17" Mac Book Pro?

It's been a while since I worked with SxS cards, but from what I recall you need two pieces of software from Sony - and I'm not sure either are compatible with El Cap: the device driver, which lets the express slot read SxS cards, and the UDF Driver to read the format the cards are written in.

More info here:

http://www.sonycreativesoftware.com/sxsudfdriver

but hopefully someone will come along with more recent experience with SxS cards.

You might try posting over on the Creative Cow Forums, you might have more luck getting a definitive (useful) answer there.

MtD

at first instal XDCAM Drive Software:

http://www.sonycreativesoftware.com/xdcamdrive

then:

http://www.sonycreativesoftware.com/xdcamdrive