remounting an unmounted disk

[bazookaman]

A guy I know has a dual 1.25ghz MDD. He's got the boot drive on the faster rear bus and another drive on the bus below the opticals. Well, he calls me and says his second drive has disappeared. First thought. He accidentally ejected it. So i told him to go to disk utility and there it is. Shows up on the left. But when he clicks mount, nothing happens. He's rebooted and the drive refuses to show up. Any ideas?

He IS using a KVM switch to share his monitor, mouse and keyboard with a PC, but i don't see how that would cause this. It causes some video wonkiness so I told him to drop the KVM and plug everything directly into the mac...just to try it.

[MacMagus]

After he clicks the button to mount the drive, does the button remain the same or does its name change to "unmount" ...?

[Seacrest]

it's probably still mounted, but just not in the sidebar.
Go->Computer in the Finder should show all volumes and you can drag it back to the sidebar.

[The Grim Ninja]

Perhaps the disk has errors and is failing to mount? Run a repair?

[Mac1337]

I had a similar problem with blank CDs. They would not mount, or so I thought. I then realized that it is on the desktop but does not show up on the sidebar. Took me a while!

[bazookaman]

Nah. It was always set up to show on the desktop. I set it up. It was my old office computer. I had been running it like that for years. Its just not showing up now.

[anonymouse1]

Master-slave-cable select set properly?

Restart?

Disk Utility?

Disk Warrior?

Reset PRAM/NVRAM/PMU?