Guest account can format HDD in WinXP!!

I have a HDD that is assigned a drive letter, but not formatted. When I log in using a Guest account and try to access it the drive, it displays a message:
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The disk in drive D is not formatted.

Do you want to format it now?
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I clicked on Yes, fully expecting to receive an access denied message, but to my total shock it let me format it. How is this possible??

And more importantly, how can I prevent it as this drive is infact an encrypted volume???

 

I think you can restrict the guest account. Open up Control Panel, and select User Accounts. There should be an option to change an account to a limited account I think. Been a while since I messed with User Accounts, so if I am mistaken, sorry!

E

 

Yep, the guest account is restricted. There's plenty of things it can't do, unfortunately formatting drives isn't one of them. I tried another test, I went out the command prompt and typed: format d: /q and it happily formatted it.

Has anyone got a spare partition they can test if this is the same for them or something unique to my setup? I'd be very greatful....thanks