I somehow lost the option to choose whether to overwrite, save or create a
duplicate file when copying.
I.E. There is already a file named Testfile. Do you want to replace that
file with the new file, keep the old file, or keep both (rename to
Testfile(2).

I know this is a simplified version of what it asks, but you get the idea.
I'm sure I clicked somewhere to "apply this option everytime", without
noticing. It's not a problem with copying say, music from one drive to
another where if it's a duplicate filename it really probably is a duplicate,
but will become a problem when copying files from my camera with which the
names are all formatted using the same scheme until I manually change them.
Any help with knowing how to reset this option?
Thanks a million!