Encrypting a backup

Why

The backup drive can get lost or end up in the wrong hands. Nobody can read an encrypted backup without the password: every file in it is stored as an encrypted file ending in .cvlt (AES-256-GCM, with the key derived from the password with Argon2id).

Before you start

You decide about encryption with the first backup. For a backup that already exists, encryption cannot be turned on or off. To change it, you have to make a new, full backup in a new, empty folder.
Think of a password of at least 8 characters and write it down somewhere safe, away from the backup drive. The password cannot be recovered or reset. Without it nobody can read the files in the backup, not even the program.
Encryption protects the content of the files. The names of files and folders and their approximate sizes remain visible in the backup.

Step by step

In the wizard, choose “History and encryption” in step 3 (see “Creating your first backup with the wizard”). On the “Backup” page:

In the “Where we write” box, choose a new, empty backup folder, or a folder that does not yet hold a backup of these folders.
In the “Data protection” box, tick “Encrypt the backup (AES-256-GCM)”.
Enter the password in the “Backup password” field and once more in the “Repeat the password” field.
If the backup should start by itself, tick “Remember the password in Windows Credential Manager”. The password goes into the Windows store tied to your account, never into the program's files or the template.
Click “Run backup”. If the backup is to be repeated, save it as a template (see “Saving settings as a template”).

Password for scheduled backups

A scheduled backup starts with nobody at the computer, so the password has to be remembered. For an existing template:

On the “Templates” page, select the template and click “Load into the form”.
Enter the backup password in both fields and tick “Remember the password in Windows Credential Manager”.
Click “Save as template”, keep the same name, and when asked “Replace the template?”, answer “Yes”.

Before every backup, the program checks that the password matches the files written earlier. If it does not, the backup does not start: one backup will never hold files under two passwords.

What you should see

The files in the backup folder end in .cvlt. They cannot be opened without the password.
The template description on the “Templates” page shows “Encryption: yes”.
When you restore, browse or record discs, the program asks for the backup password (see “Restoring files from an encrypted backup”).

What next

You delete remembered passwords in the settings (see “Deleting remembered passwords”).
The off-site backup has its own password (see “Setting up an off-site backup”).

If something goes wrong

“Enter a password”, “The two passwords do not match.” or “The password should be at least 8 characters long.”: the message below the password fields says what to correct. Once it is corrected, “Run backup” works.
“The backup of these folders in … is not encrypted. Encryption cannot be turned on for an existing backup…”: in this backup folder these folders already have an unencrypted backup. Files written earlier would stay unencrypted, so the program refuses. In the “Where we write” box, choose a new, empty folder: a full encrypted backup will be made there. The new backup starts its version history from scratch, and the older versions stay only in the old backup, still unencrypted. Delete the old backup only once the new one has been checked and you no longer need the older versions.
“The backup of these folders in … is encrypted. Encryption cannot be turned off for an existing backup.”: the same applies: choose a new, empty folder, and a full unencrypted backup will be made there.
“The password given does not match the files already written in this backup.”: enter the password used for the earlier backups. If a scheduled backup reports this error, the remembered password is out of date: remember the correct one (see “Password for scheduled backups” above).
The “Remember the password in Windows Credential Manager” box is inactive: first tick “Encrypt the backup (AES-256-GCM)”.
A notification that the backup did not start because the password is not remembered: see “Password for scheduled backups” above.
The password is lost: see “I don't remember the backup or disc password”.