"A GUID partition table (GPT) partitioning scheme is required."

[Udhai titus]

Hello,

Im trying to encrypt my LaCie external hard drive, but i get an error message.
"A GUID partition table (GPT) partitioning scheme is required."

So, I tried to change the partition under <Disk Utility> to OS X Extended (journaled, encrypted). But, now I get the error message "Running Operation 1 of 2... Name invalid. Operation failed...

Please help. Thank you.

 

[SuperSoph_WD]

Hey there, @Udhai titus!

I'd recommend you try to format the external HDD through Terminal in Mac OS. However, be aware that this would erase all your current content on the external drive. Here's the command: diskutil eraseVolume JHFS+ MyName diskX (where MyName is the Drive's name & the X in diskX needs to be changed with the number of your external drive, as listed in Disk Utility).
I'd also suggest you test your HDD for defects from the Disk Utility and see if there's anything wrong with it. It is also possible that the external might have failed, so if you have access to another Mac OS computer, try executing these procedures from there as well.

Good luck!
SuperSoph_WD