Nikon d5000 photo transfer?

I connected my camera with the usb cable… I copied and pasted the pics to another folder. It only transferred 75% of my photos.
when i viewed with a card reader, all the pics were displayed.
what's the problem with my usb cable?

If you already HAVE a card reader and it worked, why bother with the USB cable?
The card reader is the much better option, anyway.

How to transfer my photos and videos to my phone 📱.

How to transfer my photos and videos to my phone 📱.