If you have a large amount of data to back up to a offsite computer (such as another computer you own, or a friend's computer), you can save time and bandwidth by "seeding" your initial backup. Start the backup locally (which is much faster than backing up over the Internet), and then perform subsequent backups to the offsite location. This article walks you through the process of "seeding your backup".
You must have a detachable drive that you can use to transport your backup between computers to use this process.
It is important that you move / copy the entire folder that represents a computer's backup archives (the computer ID folder).
After backup is 100% complete, follow these steps on the source computer.
On the source computer on the Backup tab, click the play button for the offsite destination.
After confirming that backup resumed, the original folder destination is no longer required to continue backing up. To remove the folder destination:
If the source computer uses a different operating system than the destination computer (e.g., from Windows to Mac), make sure both computers can read and write to the drive that holds your seeded archive. If you're working with a brand new external drive, in most cases, you don't need to do anything special prior to seeding; most external drives from the factory can be accessed by Mac, Windows, and Linux.