Constant need for authentication when using MyBook on new computer

[TineL]

I'm using four WD external harddrives (a 3TB MyBook and 3 1TB passports). They have been running perfectly on my old Snow Leopard MacBookPro, but recently I got a new computer (also MacBook Pro) with Lion, and ever since I've been having trouble.

On all four external WD drives I need to authenticate every time I change something. Copying from my computer to the external drives, but also just moving something from one folder on one of the external drives to another.

Is there some setting that should be changed somewhere, or will I need to reformat the whole thing?

Thanks in advance!

NB: Should say, I'm also using external harddrives from two other companies, and they do not have the same problem.

[Wizer]

And by authentication you mean? 

[joehodge · Accepted solution]

Check your ownership status for the drive. Do you have permissions for the user that the drive is set up with? Log on to an administrator level account and check the drive by doing a Get Info <command> I (that's an "eye"). At the bottom of the Info window is the access permissions for the drive. Include yourself as read/write. You may have to check the directories and files as well but I'm not sure. If so, select all of the items at the top level of the drive, do a Get Info on this group and give yourself access to all. If ask if you want to apply these permissions to all the files and folders on the drive, respond with a Yes. That should do it. you can do this with the Terminal app but you need to be familiar with sudo chmod and chown. Good luck.

[TineL]

That did the trick. Thank you very much!