Can't Copy/Move Ext HD Files to iMac

[Joe Michaels]

I'm using a Western Digital My Book Essential Edition (500GB) external (USB 2) drive with my iMac. Previously, it was a little slow, but everything worked.

Now, I find that I cannot copy files from the WD drive to the Mac hard drive.

I get that circle-with-a-line-through-it symbol. Have never seen that before.

Neither will it allow me to copy files to a USB thumb drive (which also works with a PC).

[Xan]

Check for hard drive disk format compatibility as the disk for mat which reads on windows will not support for mac os so you will need to convert fort of drive if that is in ntfs or fat else use application that can read these format from mac os