So, El Capitan, you want to upgrade?
Whenever a new operating system is released for Windows or Mac, we inevitably get a lot of questions on compatibility and current hardware. Should you upgrade? Is it compatible? The quick and dirty answer is, no, you should not upgrade now. Wait. Please dear God, wait.
Any major operating system upgrade can fundamentally alter how audio works on your computer. The latest Mac OS, El Capitan, OSX 10.11, is a prime example of this. Apple has disabled some kernel level audio related things that are wreaking havok with a lot of currently available gear. For instance, the VSL technology on all of the Presonus AudioBox VSL interfaces now does not work. The interfaces still work, however, the VSL software is disabled. Serato has also put out a warning that there are serious issues with El Capitan, and that people should hold off upgrading for now.
That's the bottom line with all of this. Wait. If you do anything audio or video related for a living, or even just for fun, you could render all of your hardware and software completely useless by upgrading before drivers have been updated. Or worse, the drivers may never get upgraded, and then you are forced into a situation where you need to upgrade your hardware and software too.
We recommend checking with the manufacturer and the software publishers before you upgrade to El Capitan, or Windows 10, or any other operating system. Make sure they'll be compatible with your hardware and software before you upgrade. Upgrading the OS can be an easy thing. Downgrading can be a nightmare. Play it safe, and do your homework, and you'll avoid a lot of needless headaches.