Disk Doesn't show up in Finder?

Wierd thing's happening.
So an external disk i have has stop appearing in Finder, HOWEVER:
I can see it via the ls command in terminal.
It appears in disk utility.
IF i pull it out, OS X gives the improper device removal error.
Help?
Thank you.
chilkotardis
UPDATE:
IF show hidden files is on, i can see the disk.

 

I'm on Tiger so I can't advise whether or not this is good for Leopard too ...

If you go to:

Finder ~> Preferences ​

Do you have these options ticked?





If so, does your Ext HD show up in the Finder's Sidebar?

 

Yes, all those are checked, and as i said, if i enter this command:
defaults write com.apple.finder AppleShowAllFiles TRUE
into terminal, then relaunch the finder, the disk appears.
-chilko

 

I see in your specs you have both Tiger and Leopard, is this issue specific to one of those OS's? I know this isn't much but does a Permissions Repair + reboot achieve a result?

 

Try making a temporary user account, login in on that account and then attach the device.

Does it still not appear in finder?