The backup passphrase

When a backup set goes to one of your own cloud accounts, everything is encrypted on your Mac before it's uploaded, using a passphrase you choose. The cloud service only ever stores scrambled data. Storage Studio remembers the passphrase on this Mac so backups can run on their own — but it can't recover it for you, so keep your own copy somewhere safe.

When you're asked for one

The first time you choose a cloud account as a set's destination, a sheet titled Protect your cloud backup opens:

1. Type a passphrase of at least 8 characters into Passphrase, and again into Confirm passphrase. Show passphrase lets you see what you typed.
2. Tick I understand: if I lose this passphrase, these cloud backups cannot be recovered.
3. Click Save. If the set already has folders to back up, the first backup starts straight away.

Save stays greyed out until everything is in place, and a line above it says what's missing — for example "The two passphrases don't match." or "Use at least 8 characters."

You're not asked for a passphrase for a backup on a drive: that's protected with a key Storage Studio makes and unlocks for you on this Mac. Delta Trust and Delta Drive don't use one per set either — your recovery kit is what reconnects them (see The recovery kit).

%% caption: What to do about the passphrase in each situation
flowchart TD
  A{What's happening?} -->|First cloud backup for this set| B[Choose a passphrase and save a copy of it]
  A -->|The card says the passphrase didn't match| C[Re-enter passphrase…]
  C --> D{Do you have the right one?}
  D -->|Yes| E[It reconnects to your existing versions]
  D -->|No| F[Start afresh, which erases the old versions]
  A -->|You want a new passphrase| G[Change passphrase… erases the old versions]

Keeping it safe

• Write it down or save it in a password manager the moment you choose it. Storage Studio stores it encrypted on this Mac, but nobody — including Storage Studio — can recover it if it's lost.
• Choose something long rather than clever. A few unrelated words make a passphrase that's long and easy to type.
• One set, one passphrase. The passphrase belongs to the set, not the destination. If you change the set's destination, it keeps the same passphrase and you aren't asked again.

If the passphrase doesn't match

If the card says "That backup passphrase didn't match.", or that the destination "already holds a backup that was locked with a different passphrase", click Re-enter passphrase… on the card. Type the passphrase this backup was made with and click Reconnect. Storage Studio checks it first — "Checking… a cloud backup can take a minute." — and only saves it once it has unlocked the backup. Your existing versions are all still there; nothing is deleted. If it's still wrong, the sheet says so and stays open for another try.

While a passphrase is known to be wrong, automatic backups for that set wait rather than retrying over and over; Back up now and Re-enter passphrase… always try again.

Changing it

Change passphrase… is in the set's Destination menu. Because every version is encrypted with the old passphrase, changing it permanently deletes every existing version of the set, and a new backup starts from scratch. The sheet says so and the button reads Change & delete previous. Only do this if you're happy to lose the backup history — for example if you think the old passphrase has been seen by someone else.

If it's lost for good

Without the passphrase the backup can't be opened, by you or anyone else. The way forward is to erase the old versions and start again:

• Change passphrase… in the Destination menu lets you choose a new passphrase — one you'll write down this time — as it starts afresh.
• Delete & start fresh… on the card does the same but carries on with the passphrase already stored on this Mac. You have to type Delete to confirm.

Either way, your files on this Mac aren't affected.

See your settings and sign-ins are encrypted on this Mac for how Storage Studio stores secrets like this one.

See also: Where a backup can go · What backup messages mean · Data Backup