Encrypting an external USB HDD

my external USB HDD has been made both writeable and readable, I thought encrypting it was easy, I simply right clicked it in “Finder” and chose “Encrypt” put in the pw, but it then has a window that pops up and says: “A GUID Partition Table (GPT) partitioning scheme is required”
is this correct? If so how do I get the GPT for the external USB HDD? And does it make a difference to me saving files onto it, whether on pc or mac?


i read http://thetechjournal.com/how-to/tutorial-how-to-encrypt-external-drives-on-mac-os-x-lion.xhtml
and it says "Step 5: From dropdown menu choose Mac OS Extended (Journaled, Encrypted) and under Name type a name for your drive"

but l thought it had to be EX FAT to be compatible in both pc and mac? kindly enlighten me

thanks in advance

You cannot encrypt the drive on OSX and read it on Windows. If you use OSX encryption on the drive you'll only be able to read it on OSX.

In order to use OSX's encryption you'll need to reformat the drive as MacOS Extended as the system advises you.

thanks, so if want to read and write from the pw protected External HDD on a pc, l would need to transfer the files on my PW protected MacOS Extended format HDD onto computer, then erase the HDD and reformat it to EX FAT and transfer it back onto the EX FAT HDD from computer, so the exernal HDD be read and writeable on the pc?
is it not possible to just protect part of the external HDD, by having it in MacOS Extended format and rest in EX FAT format? l could create a pw disk image with files inside but that could be simply deleted.

thanks again

You might want to give something like 1Password a look. It has Mac, Windows, and IOS versions. This page has a licensing wizard to help you choose the right license as well as a link to some other licensing questions.

I realize this is not exactly a cheap option since it appears you would need a Mac and Windows version. There may be other password protection/encryption options out there with similar features.