This would only be occurring if you were running an older pre-release version of El Capitan OS X. The beta versions of OS X 10.11 were very buggy. Even the public beta which was not the final release version had this problem. It sounds like you are running this older pre-release. Please update your OS to the latest shipping version of Mac OS X 10.11 and this problem will resolve itself.
If you continue to see issues, please log a support ticket at http://support.presonus.com
so we can help you further.