Application Guide

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Formatting an External Device

When switching from a PC to a Mac you may find that you are unable to write files to an external hard drive you

had been using with your PC. If this is the case this is because your drive is formatted with NTFS, a file system

that you can only write files to with Microsoft Windows. If you want to write files to it from your Mac you will

need to reformat it.

WARNING: Formatting your drive will erase all the files currently on it. Back up all of the files on the drive

before erasing it.

 First you need to find and open the application Disk Utility. You can find Disk Utility in

/Applications/Utilities.

 Now, find your USB drive in the list on the left hand side, and click on it, the one you want to choose is

the one with its icon on the far left hand side of the column, rather than the indented one as you can

see below.

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Formatting an External Device When switching from a PC to a Mac you may find that you are unable to write files to an external hard drive you had been using with your PC. If this is the case this is because your drive is formatted with NTFS, a file system that you can only write files to with Microsoft Windows. If you want to write files to it from your Mac you will need to reformat it. WARNING: Formatting your drive will erase all the files currently on it.
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Now, click on the 'Erase' tab. Opening the 'Volume Format' drop-down menu, you can see that we have quite a few options.
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 From the drop down list shown above there are two sensible options to choose to format your disk. Choosing 'Mac OS Extended (Journaled)' (also known as HFS+) will make your drive compatible only with a Mac, and a Windows computer will not even be able to see what is on it. (Unless MacDrive or another similar program is installed on the PC.