Please follow below steps to check any issue:
(1). In Mac system information page, please check the Hardware > PCI page to see if the box is listed with driver loaded state.
(2). If raid box is detected but driver not loaded, please check the Software > Extensions page to make sure the ArcMSR.kext is listed inside.
(3). If box is detected and driver is installed but not loaded, please check your system security policy to make sure your system allows this driver been loaded. For system security setting, disable SIP, restart, install the Driver/Utility, and restart and then re-enable SIP.
Tags: Mac Pro, Mraid