[surfacto]

I spent some time setting the permission on several folders in the non-system partition so that only I (admin) would have access. However, when another user logs in, the ownership has changed on these folders to that user!
Is there a way around this?

[Angus_D]

If it's a HFS volume, no -- you should reformat it as HFS+. If it's HFS+, then that's odd. Or if it's a removable volume, that's not possible.