The phrase "unpacked boxes" means that the boxes have been brought into a place but have not been opened or their contents taken out yet. Full definition
Right now there are still stacks and stacks of unpacked boxes in the basement, so we really don't see ourselves spending any time down here in the near future. (thisisourbliss.com)
As his press secretary, Sean Spicer, was still unpacking boxes in his spacious new West Wing office, Trump grew increasingly and visibly enraged. (washingtonpost.com)
I was still unpacking boxes when, one afternoon, I heard wild screams from a crowd followed by an amplified voice booming through the open window: «Ladies and gentlemen! (automobilemag.com)