XtraFinder

About System Integrity Protection in OS X 10.11

Apple's article .

System Integrity Protection blocks code injection (and many other things).

XtraFinder works by injecting its code into Finder application process.

How to allow XtraFinder work in OS X 10.11

You need to partially disable System Integrity Protection.

I do not encourage you to disable System Integrity Protection. It makes your computer less safe.

How to partially disable System Integrity Protection

Refer this Apple's article .

Follow these steps:

1. Boot to Recovery OS by restarting your machine and holding down the Command and R keys at startup.
2. Launch Terminal from the Utilities menu.
3. Enter the following command: csrutil enable --without debug
Reboot your computer.

What the command "csrutil enable --without debug" does?

It allows code injection. That means XtraFinder can inject its code into Finder application process.

How to revert System Integrity Protection to original state

Boot to Recovery OS and enter the following command: csrutil clear