Can I reformat external Hard Drive made for PC to work on Mac?
you should be able to reformat it by plugging it in and reformatting it via disk utility in the utilities folder. If it will only be used on a mac with OS X, the most common format is Mac OS Extended (Journaled)
Yes you can do this in Disk Utility. You will need to change the scheme to GUID format.
In Disk Utility,
Select the ext. drive : click Partition tab:
Ensure the format is Mac OS Extended (Journalled)
Volume Scheme: select 1 partition, click on Options.
Choose GUID and OK and Apply.
Retrieving data ...