How can I copy my existing Time Machine backup over to a new, larger drive?
The easiest way is to just use Disk Utility in OS X!
Tip: Be sure to first format (Erase) your new drive as Mac OS Extended Journaled!
– First, turn OFF Time Machine in your System Preferences before beginning.
– Then with both drives connected, locate and click on the Restore tab in Disk Utility.
– Next, simply drag your old existing Time Machine to the Source and your new drive as the Destination. I also suggest checking ‘Erase Destination’.
Then click to Restore and wait several hours depending on the size of your existing backup.