Greetz
I searched some older threads first and decided from them to post a new thread since automounting seems both in flux and some conflicts may exist between different parts of the system.

I have some disks that I only access rarely so unfortunately I don't know when this occurred or what changed. All I know is that an NTFS partition, labeled HUGE_NT, used to be accessible by me as the sole user of this box, both as root and as user.

Now, not only can only root and not user access it, but root can't seem to change permissions on it. I've tried

and yet the root:root permissions persist, and stubbornly resist becoming user:group.

What has control over these permissions and how is it that root can't alter them, at least within the /media directory?

EDIT: What may be worse is that when user tries to access the partition a window pops up asking for unspecified permission... that is to say it does not ask for root password or user password, just authentication, and both passwords fail. Frustrating.

That _does_ sound weird. From my Slackware 14 box (same situation as you re users)
usermod -aG disk user

is the appropriate syntax. Then add them in /etc/fstab witn the 'user' option. If root can't access it, check dmesg for what's going on. Perhaps a file system issue, or you have tightened security, in which case the tight security is working:-). Root should be God on your system. It may need inserting into a windows box to check the disk filesystem. And you are mounting it ntfs-3g?

Greetz
Well of course that worked. Thank you Habitual. We used to have to declare all mounts back in the day but I'd since read that HAL/Udev/.. didn't like that. Since it just worked, I lived with it, though preferring specific declaration. Apparently this is some recent issue with ntfs-3g? As I said, it used to work just fine, now it does again. I surely hope all this reinventing the wheel, rule changing is worth it.