Information Technology Reference
In-Depth Information
• The memory stick must be Mac-formatted, which is to say it must use
the GUID Partition Table (GPT) system. Out of the box, most memory
sticks are formatted as Windows-compatible FAT32/FAT32X, which your
Mac can read and write to but cannot encrypt. Therefore, the first step is
usually to reformat a memory stick to GPT format.
• The memory stick will work only on Macs running OS X Lion or Mountain
Lion and not on Macs running earlier versions of OS X or on PCs running
Windows or Linux. To those operating systems, the memory stick will
appear to be unformatted or corrupted. For a way of creating a cross-
platform encrypted archive that you can store on a USB memory stick,
Therefore, there are two potential paths from this point: formatting and
encrypting the memory stick with GPT format or simply encrypting the disk
if it's already GPT formatted. The following instructions explain all you need
to know, although you should note that they apply equally well to any kind
of removable storage device, including FireWire, Thunderbolt, and USB
external drives.
Converting a Memory Stick to GPT and Encrypting It
The following steps detail how to first format a memory stick in Mac-compat-
ible GPT format and also encrypt it at the same time. Theoretically, these two
steps can be done separately, but it makes sense to do them at the same
time.
Be aware that files already on the stick will be deleted during the formatting
process, so you should temporarily copy them to a safe location and then
copy them back once the following procedure is finished.
1.
Start by opening Disk Utility (open Finder, select the Applications list,
and then double-click Disk Utility in the
UTILITIES
folder), and then insert
the USB memory stick you intend to use.
2.
Look for the memory stick's entry in the list of disks on the left side of
the Disk Utility window. It will probably be identified by its size. Select
the entry, but make sure you select the disk itself and
not
the partition(s),
which will be listed below and indented slightly.
3.
Click the Erase tab in the Disk Utility window. In the Format drop-down
menu, select Mac OS Extended (Journaled, Encrypted). In the Name field,
type whatever you want to call the memory stick. This name will appear
in Finder's sidebar whenever you insert the stick in the future.
