Why is one drive using 300GB more space than the other and can I clear that space to use? I have two new 3TB matching MY Book for Mac drives that I have transferred 2TB of synchronized data to from a smaller drive. When the data transferred from the first drive to the second, the computer says there is 301GB more data on the drive. The only other difference is that, due to operator error, I reformatted the first drive. That would not seem to account for a 300GB difference, but I don’t want to reformat the drive now since both are working correctly. I’d just like to have the 300GB to use.