I have a notice that HDD is full. I bought the car certified pre-owned and it's full of the previous owner's stuff I don't want. How do I delete all of it?

 

Did you get any manuals for it? This is in the Navigation manual. Mine is a 2014 Tech, I'm assuming it's the same for yours (you didn't tell us year & model).

According to my manual, it's Info->Setup->Other->Clear Personal Data. You can then select what you want to delete, apparently HDD is among the choices.

I'da thought the dealer would do that before they sold it.

 

On the 2016, it's Settings / Audio Settings / CD/HDD / Delete All HDD Data. Page 223 of the NAVi manual.