Adopt: Tell Arq to start using an existing backup set and its associated backup plan.

APFS: Apple File System, available on macOS High Sierra and later. Supports “filesystem snapshots” (see below).

Arq: The Arq application.

Arq Agent: The “launch daemon” that runs in the background (even when you’re not logged in) and does all the backup and restore work. Use the Arq application to configure it.

Arq Premium: Our subscription service which includes the Arq application with all updates, plus built-in cloud storage and secure web access to your backed-up files.

Backup plan: A plan which describes which files to back up and to where, including all options for schedule, retention, reporting, etc.

Backup record: A backup copy of your files as of a date/time.

Backup set: A set of data resulting from a backup plan, including backup records and a copy of the backup plan. The name of the folder containing the backup set is a UUID.

Detach: Tell Arq to stop using a backup plan. Arq removes the backup plan from its list of active backup plans. It does not delete any data.

Filesystem snapshot: A point-in-time, read-only instance of the filesystem. Arq can optionally create one of your APFS volume(s) and back that up instead of the live file data. This results in an backup of your files exactly as they existed at a point in time, even if the files are being modified during backup.

Snapshot: Arq 6 referred to backup records as snapshots. Arq 7 uses the term backup record (see above).

Storage location: A cloud account, network share, or local folder containing backup sets.

VSS: Windows’ filesystem snapshotting feature, similar to APFS’ filesystem snapshots. Also known as Shadow Copy.