import from hard drive

Hi, 

I have pictures saved on a hard drive (pcloud virtual hard drive).

My catalogue is saved on the same drive.

I try to import the pictures from the hard drive into my catalogue.

But I only have the "copy" import option, not the "add" which  - if I understand properly - would allow me to include the picture in the catalogue without having to duplicate them.

the "add" option works when the pictures are on another drive.

somebody knows how I can do?

thanks.