I highly recommend that anyone with a Clarion Nav unit go to clarion.naviextras.com, register, and download the Naviextras Toolbox. Supports Windows 7,8, and 10 operating systems. Didn't see a MAC version as of today.
This app allows you to back up the micro SD card that came in your unit and install map related data updates. Fixes are free; the latest map data is not free. The app runs on a computer and does require you remove the microSD card from the unit and attach it to the computer. My 2016 DSDP came with a Clarion NX405. The following picture shows where the microSD card is installed on the NX405. It is under a little trap door on the bottom left of the unit. (Pic got rotated 90 degrees during upload).
This picture below shows what the Naviextras Toolbox application looks like running on my laptop.
If you attach the original microSD card from your Clarion unit and then start the Naviextras Toolbox application, it will find the card on its own and then show "device selected". Note the "Clarion NX405" at the top of the pic below. Also note there was 1 fix available. I backed up the original contents, did the update, and backed up again. It is important to note these backup filess can be used to restore a corrupted card and presumably create a usable copy on a new card.
My laptop has an SD card slot, so I was able to insert the microSD card from the NX405 into a full size SD card adapter then directly into the computer. They also sell adapters that allow SD or microSD cards to be read via a USB port if your computer doesn't have a slot for an SD card. The following pic shows the microSD card, an SD card adapter, and an SD card to USB adapter...
BTW, You get software updates for the NX405 at
Clarion U.S.A | NX405 Software Update Instructions (for APP, MPEG and MCU)
but that is a more elaborate process and requires you have an extra blank microSD card.