DevDriveBackup

DevDriveBackup is a free, open-source Windows backup tool for developers. It backs up a Windows Dev Drive (ReFS or VHDX), code projects and any other folder to external drives, as plain file copies you can open anywhere, as encrypted versioned history, or both. You choose per folder. One window shows how fresh each drive's backup is, lets you set how much CPU and memory a backup may use, and explains every option in plain language.

• Platform: Windows 10/11, PowerShell 7.2+
• Engines: robocopy for plain copies, restic for encrypted versions
• License: MIT
• Status: working and tested on real drives; first public release

Why DevDriveBackup

Most backup tools either copy everything slowly or hide your files in a format only they can read. Developer drives make this worse: hundreds of thousands of small files, node_modules and virtual environments that rebuild anyway, junctions, Git worktrees and files locked by running tools. DevDriveBackup is built for exactly that.

What you get	How
Fast incremental copies of huge source trees	robocopy with parallel copying. Only new or changed files are copied (size and time), so a 470,000-file drive updates in minutes.
A copy you can open anywhere	The plain copy is ordinary files on an NTFS drive. No special software is needed to restore.
History when you need it	Folders you mark Versions go into an encrypted, deduplicated restic repository with every past version.
Per-folder choice	Each folder is Plain copy, Versions, Both or Skip. A folder inside a skipped folder can still be backed up.
Proof, not hope	Check backup content re-reads both sides of every file and compares SHA-256 hashes (plain copy) or verifies all repository data (versions).
Nothing deleted by surprise	Files you delete from the source stay in the copy, or, with Keep deleted for N backups, move to a dated recovery folder beside it; only the newest N recovery folders are kept.
Keep versions	Optional clean-up after each versioned backup: one version a day for N days, a week for N weeks and a month for N months (restic --keep-within-daily/weekly/monthly, counted back from the newest version so a long pause never empties the history). Dry run first; the newest version, the one just made and versions from other tools are never deleted; deleted versions free their space and the repository is checked again, and a failed check there marks the backup as failed.
Themes and size	The Look page offers Light, Dark, Sand, Ocean and High contrast, each checked for WCAG 2.2 contrast, plus Custom: pick four colours and the rest is derived so text stays readable; the page reports any pair that is hard to read. Dark themes darken the title bar, scroll bars and drop-downs too. A larger or maximised window scales everything, text included, in proportion.
Waits for AI sessions	Before a backup it looks for Claude Code or Codex sessions that worked in the last 10 minutes (their conversation files change while they work). If there are any, it names them and offers to wait and start by itself once all have been quiet for 10 minutes.
Load control for your hardware	Detects your processor and memory and offers Light, Balanced, Strong and Maximum levels, or your own threads, memory limit, parallel files and priority. You can lower the load while a backup runs: the priority changes at once, the other settings from the next step.
Several backup drives, each with its own content	One profile per drive, recognised by the drive itself rather than its letter.
Knows how fresh each backup is	The age of the last complete backup, coloured green, blue or orange against the number of days you choose.
Skips what rebuilds	node_modules, .venv, __pycache__, test and build caches, recycle bin and system folders are skipped by default; your own skips go in a personal settings file.
Safe with developer drives	Junctions and symlinks are not followed, so nothing is copied twice. Refuses a backup onto the same physical disk as the source, including the disk that holds a Dev Drive VHDX file.
Measures the backup drive	Reports model, health, file system and the real USB link speed (USB 2, 5 Gbit/s, 10 Gbit/s), and runs an unbuffered read/write benchmark.
Checks the backup drive itself	Drive check looks at four layers: what the drive reports about itself (replaced and suspect areas, errors, hours, temperature, its own self-tests), reading the disk (samples, or a resumable full surface scan), the connection (link speed, transfer errors, resets in the Windows log) and the file system. Read only.

Install

1. Install PowerShell 7.2 or newer.
2. Get the code: git clone https://github.com/razbenaharon/DevDriveBackup.git, or download the ZIP and run Get-ChildItem -Recurse | Unblock-File in the folder so Windows allows the scripts.
3. Only if you want versioned history: pwsh -NoProfile -File ./Install-BackupEngine.ps1 downloads restic 0.19.1 into bin\ and checks its pinned SHA-256.
4. Only if you want the drive's own health report in Drive check: Install health tool on that page, or pwsh -NoProfile -File ./Install-DriveTools.ps1, downloads smartmontools 7.5, checks its pinned SHA-256 and installs only smartctl into bin\smartmontools (the installer asks for administrator rights; no service, Start menu entry or PATH change).
5. Optional: pwsh -NoProfile -File ./New-DevDriveBackupShortcut.ps1 puts a DevDriveBackup shortcut with the program icon on the desktop.

Backups need no administrator rights, PATH changes or services. Only Drive check asks Windows for administrator rights, each time it runs, because reading a drive directly needs them.

Keep DevDriveBackup in a folder only you can change, for example C:\Users\YOUR_USER\DevDriveBackup. Anyone who can change its files, or rename a folder above it, can make it run their own code, and the drive check runs as administrator. A secondary drive such as a Dev Drive usually lets every signed-in account change files, sandbox accounts that tools create included, so before a drive check starts the window lists such accounts and asks first. The drive check also runs smartctl only when its SHA-256 matches the official 7.5 build.

Quick start

1. Connect the backup drive (NTFS recommended) and start DevDriveBackup.cmd.
2. New profile... and choose the drive.
3. On What to back up, Add folder... for each drive or folder, and set each subfolder to Plain copy, Versions, Both or Skip.
4. Choose a Computer load level and press Back up now.

The first plain copy is verified automatically, file by file. After that, back up whenever you like; the overview shows how long ago the last complete backup was.

How it works

Plain copy (Invoke-FastMirror.ps1) runs robocopy per selected folder with /E /COPY:DAT /DCOPY:DAT /XJ, retries once, and skips caches and links. A file that stays locked is counted and reported without stopping the run. Files that exist only in the copy are reported, and moved to <copy folder>-recovery\<date> only when you ask for it (-MoveExtras, or Keep deleted for on the overview); -KeepRecovery N then deletes all but the newest N dated recovery folders. Nothing is moved aside after a run in which robocopy failed. Verification hashes both sides in parallel and counts selected files missing from the copy. DevDriveBackup's own password, recovery-key and state folders are never copied by either engine, even when one of them is selected itself; an older copy of one found in the plain copy is named in the run's result so you can delete it.

Versions (Backup-Worker.ps1) run restic with a random 256-bit password stored for your Windows account (DPAPI) plus a portable recovery key file, a hard memory cap (Windows Job Object), CPU and I/O limits, and a structural restic check after every backup. Restore always goes to a new folder and verifies restored content.

Folder modes are stored once per source and read by both engines (Backup.Selection.psm1). The most specific entry wins, so Projects = Both with Projects\big\cache = Skip works as expected.

Mode	Plain copy	Versions
Plain copy	copied	—
Versions	—	backed up
Both	copied	backed up
Skip	—	—

Load levels are computed from your hardware. On a 12-thread, 40 GB laptop, for example: Light = 2 threads, 1 GB, 4 files at once, below-normal priority; Maximum = 11 threads, 8 GB, 32 files, normal priority.

Files

File	Purpose
DevDriveBackup.cmd, DevDriveBackup.ps1	The main window
DevDriveBackup.Theme.psm1, Backup.Taskbar.cs	Colour themes and contrast checks; the window's own taskbar button
DevDriveBackup.Data.psm1	Profiles, sources, history, freshness, load levels
Backup.Selection.psm1	Folder modes, read by both engines
Invoke-FastMirror.ps1, Backup.MirrorVerifier.cs	Plain copy and verification
Backup-Worker.ps1, Backup.Process.cs, Backup.Status.psm1	Versioned backup, check, restore, history, keys; hard memory cap; progress files
Backup-History.ps1, Backup-Security.ps1, Backup.History.psm1, Backup.Security.psm1	Versions and restore; password and recovery key windows; their safety rules
DevDriveBackup-Advanced.cmd, Backup-Manager.ps1, Initialize-BackupConfig.ps1	Advanced window for one versioned source, and its first configuration
Install-BackupEngine.ps1	Downloads restic into bin\ and checks its pinned SHA-256
Set-BackupDestination.ps1, Measure-BackupDisk.ps1, Get-BackupHardware.ps1	Drive inspection, USB link speed, benchmark, hardware summary
Invoke-DriveCheck.ps1, Backup.DriveCheck.psm1, Install-DriveTools.ps1	Drive check (runs as administrator, read only), its verdict rules, health tool installer
Inspect-DevDrive.ps1, Build-BackupReport.py	Optional size inventory and offline HTML report
New-DevDriveBackupShortcut.ps1, New-DevDriveBackupIcon.ps1, DevDriveBackup.ico, design/icon	Desktop shortcut; the program icon and its vector sources
Test-*.ps1, .githooks, .github/workflows	Tests, the privacy hooks and the checks that run on every push
config.example.json, BACKUP-SYSTEM.md, CHANGELOG.md, THIRD-PARTY.md, LICENSE	Example configuration, versioned engine details, changes, third-party software, license
profiles.local.json, jobs\*.local.json, backup.local.json	Your personal settings (git-ignored)

Personal skips go in a job file: Exclude takes folder names (wildcards allowed) or paths below the source, and NeverBackUp lists folders that are never backed up by either engine, such as a folder holding credentials. See config.example.json and BACKUP-SYSTEM.md.

Frequently asked questions

How do I back up a Windows Dev Drive? Add the Dev Drive (for example E:\) as a source in DevDriveBackup and back it up to an external drive. Back up the files inside the mounted drive, not the .vhdx file while it is in use. DevDriveBackup refuses to put the backup on the physical disk that holds the VHDX.

Does it compress my files? The plain copy does not; it is an ordinary file-for-file copy. Versions are compressed, deduplicated and encrypted by restic.

Does every backup read all my files again? No. Plain copies compare size and modification time and copy only what changed. Check backup content is the separate, slower step that reads everything and compares hashes.

What happens to files I delete? By default they stay in the plain copy, and versions keep them in older snapshots. Two settings on the overview clean up instead: Keep deleted for N backups moves them out of the plain copy into dated recovery folders and keeps the newest N; Keep versions keeps one version a day, a week and a month for as long as you choose (for example 7 days, 4 weeks, 3 months) and deletes older versions after each backup.

Will it slow down my computer? Choose the load. Light uses about a sixth of your processor threads at below-normal priority so your programs come first; you can switch levels during a backup.

How do I restore? Plain copy: open the folder on the backup drive and copy files back. Versions: Versions and restore in the window, or restic restore with the recovery key on any computer.

Can I use several backup drives? Yes. Each drive has its own profile with its own folders and its own freshness.

How do I know the backup drive itself is healthy? Open Drive check and run a Quick check (a few minutes). For a full answer, run a Full surface scan: it reads every part of the drive, takes hours, and can stop and continue later. Many USB boxes do not pass the drive's own health report on; then that part shows Not available and the full scan answers the same question: are there places that cannot be read. DevDriveBackup writes nothing to the drive; only Windows' own file system scan may note problems it finds.

Is there a scheduler or reminder? No, by design. You decide when to back up; the window shows how old each backup is.

Tests

Each test uses disposable folders and uniquely named folders on the destination drive and never touches your real backups:

pwsh -NoProfile -File ./Test-DevDriveBackup.ps1 -DestinationDrive Y      # window data layer, both engines
pwsh -NoProfile -File ./Test-BackupSelection.ps1 -DestinationDrive Y   # per-folder modes in both engines
pwsh -NoProfile -File ./Test-BackupSystem.ps1 -DestinationDrive Y      # versions, restore, history, prune
pwsh -NoProfile -File ./Test-BackupSecurity.ps1 -DestinationDrive Y    # password change and recovery keys

Test-BackupCopyRules.ps1, Test-BackupActivity.ps1, Test-BackupTheme.ps1, Test-BackupRetention.ps1 (its real restic part runs where restic is installed), Test-BackupDriveCheck.ps1, Test-BackupHistory.ps1, Test-BackupStatus.ps1, Test-BackupSecuritySafety.ps1 and Test-BackupResourceControls.ps1 need no drive and run in CI.

Keeping your own details out of a fork

Test-PrivacyGuard.ps1 refuses volume identifiers, user-profile paths, personal email addresses and force-added git-ignored files. On your computer it also reads your git-ignored *.local.json files and %LOCALAPPDATA%\DevDriveMirror\hardware.json and refuses their specific values (drive models and labels, key identifiers, folder names, computer name), without ever storing them in the repository. CI runs it on every push; to run it before every commit and on every commit message, turn on the hooks once per clone:

git config core.hooksPath .githooks
pwsh -NoProfile -File ./Test-PrivacyGuard.ps1 -ListTerms   # show the private values it protects

Limitations

• Windows only. The window and messages are in English; file names in any language are preserved.
• Backups read live files; there is no VSS snapshot. Close databases or export them before backing them up.
• The plain copy keeps file contents, timestamps and basic attributes, not NTFS permissions or alternate data streams.
• One backup drive cannot protect against its own loss. Keep a second drive or copy somewhere else.

License

MIT, see LICENSE. restic and Chart.js are separate projects under their own licenses, see THIRD-PARTY.md.