A file is not safely backed up while it exists in only one place, even if that place is a brand-new external drive.
What 3–2–1 means
The 3–2–1 method is easy to remember: keep three copies of the important files, store those copies on two different types of media, and keep one copy off-site.
For an All Digital Productions delivery, the first copy may be the verified folder on your computer. The second may live on an external hard drive or SSD. The third may live in reputable cloud storage or on a separate drive stored at another secure location.
Copy the files to an external drive
Connect the external drive and wait for it to appear in Finder on Mac or File Explorer on Windows. Create a clearly named folder such as “All Digital Productions — Event Name — Final Delivery,” then copy the complete downloaded folder into it.
Do not move the only copy. Copy it first, wait for the transfer to finish, and open several files directly from the external drive. Only after verification should you consider removing temporary working copies.
- Use a drive with comfortable free space beyond the current delivery
- Keep the original folder organization
- Leave the computer connected to power during large transfers
- Safely eject the drive before unplugging it
- Label the drive with its contents and the backup date
Why two types of media matter
Two folders on the same computer are not two backups. Two partitions on the same physical drive are also vulnerable to the same hardware failure, loss, theft, or accidental damage.
Different storage types do not need to be complicated. A practical household plan might use internal computer storage, one external hard drive or SSD, and encrypted cloud storage. What matters is that one incident cannot remove every copy at once.
Keep one copy off-site
An off-site copy protects against risks that affect an entire location, including theft, fire, water damage, and electrical events. Cloud storage is convenient when the account uses a strong unique password and multi-factor authentication.
A separate physical drive can also serve as the off-site copy when it is stored securely somewhere else. Bring it back periodically, update it, verify it, and return it to the off-site location.
Backups must be tested
A transfer that appeared to finish can still be incomplete, and any storage device can eventually fail. Open a sample of photographs, play videos, compare folder sizes when practical, and watch for error messages.
Set a recurring reminder to connect each drive and review the backup. As computers, connectors, and storage services change, migrate the files to media you can still access.