I have recently bought an iMAC and am still very new with everything there is to learn . Some things are not so easy to figure out - and so I'm asking hopefully those who know about MACs. I have a 1TB Seagate Portable Hard Drive that I have had for about a year and it has worked great for me . I use it to store all of my photos on it since I take so many - especially with my growing family . I have all my pictures organized by year, then by month, then day . It cleaned my PC right up and it works great . Worked great . I now have a MAC OS X 10.7.2 - the iMAC thing . I have for the first time since I've had it, uploaded my pictures off my camera (which was not as easy a thing as I was use to on my PC) , and would now like to store them on my PHD in the appropriate year/month/day folders ........ But , I went to go open the folders and delete some silly pictures that I wanted gone , and it won't let me delete anything . It says its locked . So I tried to add a folder to my December folder for 2011 , and it won't let me add anything to it either . I am scared to put my pictures on the hard drive and delete them off my camera because I don't know if they will transfer over correctly and if they do - I don't know if I can access them later . Also , I want to put them in the right dated folders so I can keep track of them and the time they were taken . Does anyone have any idea why this is going on ? Is there something I am not doing that I don't know about ? Can I only use my PHD on a PC ??? I wouldn't think so - But I am very confused . Pleeeaassseee help me .