I have an external drive with all my photos on. I copied them all to a second drive and re arranged them into a better folder structure. However, before I delete the original drive and use the new as my master copy I want to make sure every picture in the original drive has a match in the new drive. Any idea of software to do this? I need to be very sure as this is literally every picture I have since birth. Many thanks ps (I have tried importing the new drive to lightroom and then bringing up the import dialogue for the original drive, where don't import duplicates is selected. However, I am not entirely sure this method is foolproof so I need another way to double check).