Backup Labs

Backups for Windows that you set up once and stop thinking about. Pick any folders (or whole drives), pick where the backups go, and Backup Labs keeps them, on a schedule, when files change, or when you plug in the backup drive.

Download the installer — Windows 10/11, x64. Installs for every user in C:\Program Files\ProtagonistLabs\Backup Labs (installing and updating ask for admin rights once). The app updates itself. Screenshots, a comparison with other backup tools and the full guide: protagonistlabs.app/backuplabs.

What it does

• Incremental backups you can browse. Every backup is a normal folder named by its date. Files that didn't change are NTFS hard links to the previous backup, so they take no extra space, and any backup can be deleted without breaking the others.
• Or archives: one .bkl file per backup with four compression levels, or encrypted (AES-256-GCM, key from your password with PBKDF2-SHA256, 600,000 iterations). A plain .bkl is an ordinary zip inside: 7-Zip and other archivers open it as it is, and renamed to .zip it opens in Explorer, so your files stay reachable without Backup Labs. Encrypted archives open only in Backup Labs, and only with the password. Backups made before 1.3.0 as .zip are still listed, restored and pruned.
• Double-click a .bkl and it opens in Backup Labs, on the Restore panel for that file, wherever it is: restore it whole into a folder, or find one file in it. An encrypted one asks for its password. A backup in one of your jobs' destinations can also go back to its original places.
• Several jobs, each with its own folders, destination, format, schedule and retention.
• When: manually, hourly, every 6 hours, daily at a time you choose or weekly on a day and time you choose; a minute after files change; and when the backup drive is plugged in (found again even if it comes back under another letter). If the PC is off or asleep at that time, the backup runs once when it is next on. A new job never starts by itself while you set it up: it waits for its first time, or for "Back up now".
• Back up our apps' data: one click makes a job for the settings and data of the Protagonist Labs apps on this PC (%APPDATA%\ProtagonistLabs, where every studio app keeps its data), leaving out covers, trailers and caches the apps download again. It asks only where the backups go; a second click opens it.
• Smart retention: everything from the last day, one a day for a month, one a week for a year. Or simply the last N.
• Exclusions: node_modules; *.tmp; C:\Users\me\AppData.
• Open files (Outlook .pst, databases) through a Volume Shadow Copy. Windows asks for administrator permission at each such backup.
• Restore a whole backup to the original places or to another folder, or find one file and bring back any of its versions.
• Clone a drive: an SD card, a USB stick, a hard disk or SSD, sector by sector, to a raw .img (Etcher, Win32 Disk Imager and dd read it) or straight onto another disk, and an image back onto a disk. Every sector, or only the space NTFS uses. The disk Windows runs from can be copied (through a shadow copy), never written to. Onto a bigger disk, the GPT backup table moves to the new end, a recovery partition at the end moves along, and the partition before it grows, file system included; onto a smaller one, as long as the partitions fit. Verified by reading everything back. Needs administrator permission.
• Lives in the tray, starts with Windows if you want, progress bar and cancel for everything.
• Works with SpaceScan: it names your backup folders and the folders you back up, backs a folder up from its row menu, and opens on a backup drive that's full.
• Works with Stash: its Thunderbird and Firefox backups get versions here, on another disk or NAS. Stash hands over its backup folder as the job "Thunderbird backups (Stash)"; before each run that job is pointed at the folder Stash names in %APPDATA%\ProtagonistLabs\data\stash.items.json, so moving the folder in Stash needs nothing here.

Nothing leaves your computer: no account, no cloud, no telemetry. The only network call is the update check against this repository's releases.

Build

Needs the .NET 10 SDK and Inno Setup 6.

.\build.ps1            # engine tests, self-contained publish, dist\BackupLabs-<version>-setup.exe
dotnet run --project tests   # engine tests alone

The version lives only in <Version> in Backup.csproj. A release is gh release create v<version> dist\BackupLabs-<version>-setup.exe; the updater picks up the latest release whose asset ends in setup.exe and checks it against the SHA-256 GitHub publishes.

Layout

File	What
Engine.cs	backup, retention, restore, file versions, shadow copies
Crypto.cs	the encrypted archive stream, the saved password (DPAPI)
Program.cs	entry point, USB drive tracking, the elevated run for open files
Jobs.cs	jobs, settings (and reading older settings files), when a job runs (Schedule)
Ecosystem.cs	the shared %APPDATA%\ProtagonistLabs folder: card, jobs file, sister apps, the apps' data job
MainWindow.xaml(.cs)	the window, tray, scheduling, real-time watching
Updater.cs, UpdateDialog.xaml	self-update from GitHub releases
installer/	Inno Setup script and the icon generator
tests/	engine checks (--vss <file> runs the shadow-copy check, needs admin)

Settings and the log are in %APPDATA%\ProtagonistLabs\Backup Labs (moved there from %APPDATA%\BackupLabs in 1.6.0, by the installer or at the first start).

Archives are <date>.bkl. Plain or encrypted is told by the first 8 bytes (BKLENC1\0 = encrypted, see Crypto.cs), never by the extension. The installer registers .bkl for every user (HKLM\Software\Classes\.bkl → BackupLabs.Backup, "Backup Labs backup", the app's icon) and removes it on uninstall; opening one runs BackupLabs.exe --open "<file>", which a running copy takes over.

For UI checks only: BACKUPLABS_TEST_ROOT=<folder> runs a separate copy whose settings, log and ProtagonistLabs folder live in that folder, with its own single-instance names and no autostart writes, so it never touches or hands its arguments to your own Backup Labs.

More from Protagonist Labs

• SpaceScan: see what is filling up a drive, free.
• File Labs: a free dual-pane file manager.
• All apps: Windows apps that each do one job properly.