I have Time Machine making encrypted backups to a 1TB drive. I used Time Machine just a little bit ago and noticed two things since encrypting the drive: 1) The tick marks on the right of the screen are now alternating colors between purple and gray, why? And 2) the purple and gray tick marks differ in time by a 3-4 minutes each. Can anyone explain why this is happening? Edit: Found the difference: gray tick marks are local backups and purple tick marks are backups that have actually been stored on the external drive. I thought local backups were made only when the external drive was not available, and then as soon as that drive became available Time Machine would move the local backups to the disk. Has this changed? Or has that never been the case?