I need to use my external hard drive to move files from PC computer to my Imac which i recently purchased. I am actually able to copy files from PC to external hard drive to imac but i cannot do opposite way. The prompt says my external hard drive cannot be modified from OSX. Is there a setting that i can make my external hard drive be able to modify?
To add to Peter's advice... run Disk Utility and Repair Disk Permissions. Disk Utility is in your Applications/Utilities folder.
Launch Disk Utility. Select MacintoshHD in the panel on the left, select FirstAid, then click: Repair Disk Permissions. Quit DU when it's finished and reboot.
One of the reasons why u cannot copy files to your external hard drive is, maybe your external hard drive is formatted as NTFS, if your using Mac OS x 10.5 probably it is formatted as Mac OS X extended
(or maybe Journaled), by the rules, Mac OS X can read NTFS files but cannot write into it, if ur external drive is formatted by FAT 32 maybe it will work, but I'm not 100% sure. But for the first part, I'm sure of that because I had a recent experience with it, and it resolves my problem, for that, u have to format your external drive by Mac OS X extended or journaled so that u can write files to it, this can be done by the Disk Utility. Hope this will help.