Sometimes you might face a problem while creating a new folder on the macbook desktop. When you do "new folder' it first asks for the password and then fails with the "you do not have the necessary permission" message. You may be using the only user account that has been created on the Macbook Pro since it was installed. It is defined as an Admin account.
You may have tried reseting the Permissions and ACL using the Terminal program after interupting a re-boot. That didn't have any affect though. Also tried changing the privileges by right clicking on the desktop and going in via Get Info...again.
We have solution for this problem.
Turns out that the under the "General" section of Get Info for the Desktop there is a tickbox called 'Locked' - it was ticked? and now you have to un-tick it. Now You are able to create New Folders without trouble.