[Thomas Bresinsky]

I also had problems with my SxS Pro+ cards from my PMW-F5 and El Capitan 11.10.1.
SxS cards did not mount. We where in the middle of an interview with a 94 year old shoah witness. In 4K and ran out of disk space.

My guess was my SxS driver was not working with El Capitan 10.11.1. So I downloaded SxS device driver v2.0.0.06260, installed it.
After that my MacBook Pro (Late 2011) with El Capitan 11.10.1 didn’t boot any more.
I just got a white screen. – Despair guaranteed!
Luckily we managed to rent further SxS pro+ cards in the last possible moment.

Today my mac guru recommended to start the MacBook Pro without extensions (pressing down “shift”-key).
I DEINSTALLED SxS device driver. After this my MacBook Pro worked fine again in El Capitan 11.10.1. Just as usual. “Repair” in disk utility found nothing.

I tried to INSTALL SxS device driver v2.0.0.06260 one more time. Just to give it one more try.
This time installation was successful! MacBook Pro started up. No problems!
SxS pro+ cards mounted in my express card slot.
I could copy the 4K xavc files and look at them in Sony Contend Browser 2.0.
Everything is working fine now. Why?
No idea!
Perhaps deinstallation of SxS driver deleted some orphaned extensions!?

So my recommendation now would be to run the deinstallion process with SxS device driver installation utility before actually installing the new SxS driver version.

Hopefully my system keeps working.

MacBook Pro Late 2011
Mac OS X 10.11.1 El Capitan
SxS driver v2.0.0.06260

Thank you all for your help