How to Partition a Portable Hard Drive for Windows & Mac Files

Portable hard drives are a popular choice for storing back-ups and for transferring data from one computer to another. Because they are external, they can be connected and disconnected easily -- sometimes even while the computer is on, as is the case for drives connected over a Universal Serial Bus (USB) interface. However, when transferring data between computers running different operating systems, you must choose the portable drive's file system very carefully. The file system you use to format the portable drive must be accessible by any of the operating systems running on the computers involved, and it must also accommodate the size of the drive's partition. FAT32 is a file system developed by Microsoft. You can make a portable drive usable on both Windows and Mac computers by formatting it with a FAT32 file system. The graphical Windows user interface does not implement this capability automatically, but you can create such a file system by using the command line.

Step 1

Connect the portable drive to the Windows computer.

Step 2

Log-in to the Windows computer as a user with Administrator rights. Click on "Start," then click on "My computer." Make a note of the drive letter (for example, "D:") assigned by Windows to the portable drive. The portable drive must be eight terabytes or less in size.

Step 3

Click on "Start," then click on "Run." Type "cmd" on the Run window's empty field, then press "Enter." Click anywhere within the black portion of the new Command window.

Type the following command into the Command window:

format /FS:FAT32 L:

Replace "L:" by the drive letter identified in Step 2. Press "Enter." Windows will take a significant amount of time (dependent upon the size of the drive) as it formats the drive with a FAT32 file system. When the Command window prompts you again for a command, the formatting will be complete. The portable drive will be ready to use both on Windows and Mac computers, as both can access FAT32 file systems natively.

References

• Microsoft: Limitations of FAT32 File System

About the Author

Jonah Quant has been writing about computer science since 1990. He has contributed to international conferences and journals such as those of the Institute of Electrical and Electronics Engineers and the Association for Computing Machinery. Quant has a Ph.D. in computer science from the University of California.

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