How backups work
Hourly snapshots of your whole Mac, what is included, what is left out, and how versions are kept.
Every hour, a snapshot
Once an hour Yester takes a snapshot of your Mac’s data volume — a frozen picture of every file at one instant — and backs up from that snapshot rather than from the live disk. That means a file that changes halfway through a backup is still captured consistently, and the backup never slows down what you’re doing.
Only what changed since the last backup is uploaded. Files are split into small pieces, so editing a large file uploads only the pieces that differ. Everything is compressed and then encrypted on your Mac before it leaves; see Security and the recovery key.
What is backed up
The whole Mac: your home folder (Documents, Desktop, Downloads, Pictures, Music, Movies), other users’ home folders, Applications, Library folders (mail, messages, app data and settings) and system settings. macOS itself is not backed up — it comes from Apple, and a new Mac already has it.
What is left out
- Caches, logs, temporary files and the Trash.
- Files that live only in iCloud and aren’t downloaded to this Mac (Yester lists these in Settings so you know).
- Anything you exclude yourself, under Settings → Exclusions.
- Files that are open in a way that stops them being read consistently. Yester retries them at the next backup and tells you on the Overview screen (“2 files are waiting”).
Easy on your Mac
Backups pause on battery power and slow down during video calls. Between backups the helper is idle. On the first backup, the most important things go first so that a Mac that dies on day one still has its documents saved.
Versions and how long they’re kept
Every hourly backup is a version you can go back to. To keep the history useful rather than enormous, Yester thins it as it ages: every hour for the last 24 hours, then daily for 30 days, then weekly until the end of your plan’s window. Deleted files stay restorable for the same window.
The current state of everything you pay for is kept for as long as you pay — whether the Mac is connected or in a drawer. The plan window only governs how far back you can go for older versions and deleted files. See Plans and history windows.
Nothing on your Mac can delete a backup
Your Mac can add to its backup and read from it. It cannot delete from it — the credentials it holds don’t allow it, full stop. Deletion happens only on Yester’s side, by the retention rules, when a version passes your plan’s window, with a 30-day safety net behind even that. Ransomware that encrypts your Mac cannot reach the versions from before it struck; a mistake at two in the morning can’t either.
The weekly restore check
Once a week Yester restores 50 randomly chosen files from your backup and compares them byte for byte with what it uploaded. The result is on the Overview screen: “Restore check passed yesterday · 50 sample files matched”. If a check ever fails, Yester tells you and the file is backed up again.