Just bought an iMac (which I LOVE!) and am in the process of moving files from my old Windows XP computer. Both computers are available on my network, hardwired. Over the course of the last few years, I have manually backed up my photo files to a Simple Tech external hard drive from the XP computer. I was not sure how to move all these photos, but plugged in the Simple Tech drive into the Mac and to my surprise, I could see all my photos, was able to drag them into iPhoto and it was much simpler than I thought it would be. However, I can't seem to make it work the other way. Drag a photo from the iMac onto the Simple Tech drive. I assume, now, after reading up a bit on formatting, that the Simple Tech drive is formatted for the XP and that is probably why it only goes in one direction. Or is that not the reason and I'm just not doing it right. I would like to purchase a WD My Passport for the Mac and wonder if I will be able to drag and drop photos from my Mac back to my Windows computer the same way I could with the Simple Tech drive. I know I can format the Passport Essential for both Windows and Mac, but then will it work with Time Machine? Appreciate any thoughts on this, hopefully non techie as I'm still pretty new to this.