cannot change permissions on Seagate harddrive

I've done Cmd+I (get info).

It says I have read and write access.

I've opened the padlock.

It still says I don't have necessary permissions to make changes.

The more action button is ghosted.

It's my hard drive, my files, I still have the receipt.

My Macbook OS is up to date.

I'm just trying to drag/drop some photos, but it's not allowing me in.

Please advise.