So I got my new rMBP on Monday and today I formated my Seagate hard drive for use with Mac. I went to the website in the manuel and set it up for Mac only. So in Time Machine under options where you can exclude folders, it says the estimated size is about 56.33GB. Under my storage in About This Mac, it is the amount of space used. About 193GB of about 250GB (rounded to whole number). It is currently backing up but it says out of 38GB. I don't know why. I didn't exclude anything so it should be backing up my whole system but it doesn't look like it is. Any ideas?