HTC One User Manual page 201

USB When you plug in an external USB storage device (such as a
storage USB flash drive or an SD card reader), you can view photos
and videos stored on the device right from Gallery and play
songs stored on the device in Music. You can also open PDFs
and edit Office documents.
You need a special cable to connect HTC One and a USB
storage device. HTC One supports USB storage devices
(except portable hard drives) up to 64 GB.
Copying files to or from HTC One
You can copy your music, photos, and other files to HTC One.
Save and close your files before copying them from your
computer to HTC One, or vice versa.
1. Connect HTC One to the computer using the supplied USB cable.
You'll see options for viewing or importing files on the computer
screen.
2. Choose to view files.
3. Copy the files from your computer to HTC One, or vice versa.
4. After copying the files, disconnect HTC One from the computer.
Storage 201