[tsugi]

It's a security setting to stop unpleasant downloads getting into the root system. It's only been around since 10.11

It is advised that it is left alone, but it is a workaround for the AVB situation, of which Avid are aware and are in communication with Apple. I disabled mine, as while the S3 was once again behaving as a DAW controller, the price tag seemed a bit high for that, and I really wanted it as an interface also! In addition to that, I am pretty restrictive in from whom I download things.

Reboot holding Cmd-R

In Utilities on the toolbar, open Terminal:

type csrutil disable
Hit Return and reboot.

To reset it, as above, but type csrutil enable

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