Copying USB drive

Hi all I have a lot of files 321GB I save on different external drives all USB3 the type that doesn't need external power IE powered by USB ........ my problem is that when I update one copy say with new files, when I try copy paste updated copy to any other saved copy it wants to rewrite all files not just the updated ones what am I doing wrong ? any help advice welcome

RolandJS said:

Are you using Windows' explorer.exe? Unless something has happened, the first "fork in the road" -- the first file that encounters a similar name but with different size and/or different date -- should generate a popup that gives you the option to update all with similar size/date mismatch and not copy the files that have the exact same size/date files. I hope somebody can explain it better than I just did - I'm in a classroom with a March of the Penquins movie speaking all over the place.

something similar to what I think u said use to happen explorer would ask me if I wanted to copy replace same files to which id say no and just new files where copied ???? taking no time at all now want's to copy for hours ??

RolandJS said:

Well, if there are lots of changed files, that could take some time; especially when piping through the usb port, 3,2, or otherwise.

this is something new happening it didn't use to be this way explorer doesn't ask me for instance do I want to copy same file or replace it anymore ?