Proxmox Backup Client — Windows and Linux client for Proxmox Backup Server

🇬🇧 English · 🇫🇷 Français · 🇮🇹 Italiano · 🇩🇪 Deutsch · 🇪🇸 Español · 🇷🇺 Русский · 🇨🇳 中文 · 🇯🇵 日本語 · 🇬🇷 Ελληνικά · 🇷🇴 Română · 🇸🇪 Svenska · 🇸🇦 العربية · 🇮🇷 فارسی

⚠️ Disclaimer: This project is not affiliated in any way with Proxmox Server Solutions GmbH. "Proxmox", the Proxmox logo and related names are the property of their respective owners; here they are used only to state compatibility. See proxmox.com for their products.

📦 Download

👉 Download the latest release

⚠️ Windows shows "virus detected" (e.g. Trojan:Win32/Sabsik.FL.A!ml) or a SmartScreen warning?

This is a known false positive for Go/Wails applications — it is not a virus. The !ml suffix indicates a machine-learning model detection that flags unsigned and uncommon executables.

See why this happens and how to verify the download.

🔎 Verifying any download

Every release provides SHA-256 checksums and a signed provenance attestation (cryptographic proof that the binary was produced by this repository's CI, from a precise commit):

Get-FileHash .\ProxmoxBackupClient.exe -Algorithm SHA256   # compare with SHA256SUMS.txt
gh attestation verify .\ProxmoxBackupClient.exe --repo tizbac/proxmoxbackupclient_go

VirusTotal — 0 detections. Independent multi-engine reports of recent MSI installers: 0.2.108 · 0.2.107 · 0.2.106

ℹ️ Code signing: Windows binaries are not yet Authenticode-signed (an OSS certificate via SignPath Foundation is pending). In the meantime, provenance is established through the attestation and checksums above.

✨ Features

GUI — Proxmox Backup Client GUI (recommended)

• 🌍 Multilingual — French, English, Italian, German and Polish interfaces
• User-friendly configuration with connection test
• Real-time backup progress with throughput and time remaining
• VSS (Volume Shadow Copy) support for consistent backups
• Multi-folder backups, file and disk modes
• Snapshot browsing, file search (wildcards) and restoration
• Multi-PBS server support with certificate fingerprint pinning (TOFU)
• Windows service mode + scheduled backups
• Backup cancel, history (last 6) and rerun
• Debug logging for diagnostics

CLI tools

• proxmoxbackup-directory — directory (PXAR) backups with deduplication
• proxmoxbackup-machine — full live Windows machine backups (FIDX, VSS, incremental)
• proxmoxbackup-nbd — NBD server for restoring disk backups (Linux)

📸 Screenshots

!Server configuration Multi-PBS server management with status indicators

!Add server form Simple server configuration with connection test

!One-shot backup Real-time backup progress with ETA and throughput

Smart system exclusions (file mode)

System folders: System Volume Information (VSS storage, can reach 100+ GB), $RECYCLE.BIN, Recovery. System files: pagefile.sys, hiberfil.sys, swapfile.sys.

Why this matters: a drive may show 1.03 TB used while real files are ~141 GB. Without exclusions the backup would include VSS snapshots (wasted space and time); with them, the size matches the real data.

Recommendation: use file mode (default) with auto-exclusions for file-level backups; use disk mode in a separate job for bare-metal restoration (includes everything).

Security & quality

• Input validation and credential sanitization
• Path traversal prevention
• Retry logic with exponential backoff
• Comprehensive error handling and tests, 100% lint compliance

🚀 Quick start (GUI)

1. Download ProxmoxBackupClient.exe (or the .msi) from the releases
2. Launch it (no admin rights needed to start: it asks for elevation only when something actually requires it — the service token, or VSS machine backups)
3. Configure your PBS connection and test it
4. Select the folders to back up
5. Start the backup

🪟 Unattended / silent install (MSI)

The MSI honours Windows Installer's standard silent switch, plus public properties for every default:

# Silent install with the defaults (service: Automatic + started; GUI autostart enabled)
msiexec /i ProxmoxBackupClient.msi /quiet
Silent install that installs the service but does NOT enable/autostart it
(created as Manual and left stopped) and skips the GUI autostart entry too
msiexec /i ProxmoxBackupClient.msi /quiet AUTOSTART=0 SERVICEAUTOSTART=0
Custom directory + verbose install log
msiexec /i ProxmoxBackupClient.msi /quiet INSTALLFOLDER="D:\Apps\ProxmoxBackupClient" /L*v "C:\Temp\install.log"
Silent uninstall (KEEP_CONFIG=0 also purges %ProgramData%\<name>)
msiexec /x ProxmoxBackupClient.msi /quiet KEEP_CONFIG=0

| Property | Default | Meaning | | --- | --- | --- | | AUTOSTART | 1 | 0 = no GUI autostart entry at logon | | SERVICEAUTOSTART | 1 | 0 = service installed as Manual and left stopped — installed, but never enabled or autostarted | | KEEP_CONFIG | 1 | Uninstall only: 0 = also delete the %ProgramData%\ state directory | | INSTALLFOLDER | Program Files | Installation directory (also editable in the UI) |

Run elevated (admin); exit code 0 = success, 3010 = success + reboot required. The branded MSIs (NimbusBackup.msi, AcmeBackup.msi, EtitechBackup.msi) take exactly the same switches.

NEW! — Full machine live backup

New functionality has been added that now allows backing up a complete Windows 10/11 system, or Linux machine, and their respective server versions without any downtime.

The command syntax is mostly the same, except -backupdir string.

In the case of machine backup executable there's in place of backupdir, -backupdev. For example an invocation could be:

machinebackup.exe -authid yourapikey -backupdev \\.\PhysicalDrive0 -baseurl https://yourpbs:8007 -certfingerprint xx:xx:xx... -datastore zfs -secret L4m3r -backup-id testfull1

The above command will look at Disk 0, detect all mounted partitions, take a VSS snapshot of these, and then create a bootable backup image of the whole disk as FIDX.

The next backup will be incremental, hashing has been parallelized so speeds of 1 GB/sec can be easily reached.

Linux machine backup prerequisites

Windows machine backup uses VSS. Linux has no VSS, so a machine backup of a running Linux host needs the elastio-snap kernel module (a fork of dattobd) to take a point-in-time snapshot of the block device while it is being written to. dattobd itself also works if it is already loaded.

The original elastio/elastio-snap repository is archived and no longer builds on current kernels (we hit this on Debian 13, kernel 6.12). Use the maintained fork, Axcient/elastio-snap (branch develop). Version 0.12.11 of that fork built and ran on Debian 13 with kernel 6.12.

Two things are required, or a Linux machine backup refuses to run:

1. The kernel module must be installed and loaded. Building from source:

sudo apt-get install linux-headers-$(uname -r) build-essential   # Debian/Ubuntu
   git clone --depth 1 https://github.com/Axcient/elastio-snap.git
   cd elastio-snap
   sudo make
   sudo make install
   sudo depmod -a      # make install does not run depmod, and modprobe fails without it
   sudo modprobe elastio-snap
   lsmod | grep elastio_snap

1. The backup must run as root. The module's control interface is root only, and machinebackup refuses to take a snapshot as a normal user. A plain file or directory backup does not need root.

File restore — NEW!

File restore is possible by using the nbd tool.

In order to use nbd please first do modprobe nbd max_part=0.

For unknown reasons, using max_part != 0 causes an infinite partition probe loop.

The NBD tool will connect any fixed disk backup, regardless of it being a VM or host backup (that being said, it also works for PVE backups).

To use it use a command line similar to this: ./pbsnbd -authid 'apikey' -baseurl https://yourpbs:8007 -secret 'yoursecret' -certfingerprint 'aa:...:xx' -datastore test -namespace test1 -path "vm/107/2025-08-02T23:13:01Z/drive-virtio0.img.fidx"

If you omit -path, a terminal UI will show up allowing you to select the fidx file.

Beware to not use this on a machine running important stuff (a corrupt filesystem can crash the OS potentially, that's why Proxmox VE uses a QEMU instance for this).

Also be very sure to have unmounted anything on the nbd disk before stopping pbsnbd, if not you will likely end up with a busy unmountable partition. If someone has an indication of how to recover from that, please tell me.

If you get a Device or resource busy error, you have to force disconnect by running nbd-client -d /dev/nbd0 or simply reboot.

Restore to physical machine

A live CD / PXE boot system will be released that will allow logging in to a PBS server, selecting the backup, and launching clonezilla. For now the best way is spinning up a clonezilla live and copying to it the nbd server executable; before proceeding with clonezilla, on another tty, you launch pbsnbd.

I suggest also copying over command line parameters such as authid, baseurl, fingerprint etc, they are a pain in the... to hand type!

Once pbsnbd is up and running, you can use the clonezilla disk-to-local-disk option.

Usage — Directory Backup

A typical command would look like:

proxmoxbackupgo.exe -baseurl "https://yourpbshost:8007" -certfingerprint pbsfingerprint -authid "user@realm!apiid" -secret "apisecret" -backupdir "C:\path\to\backup" -datastore "datastorename"

proxmoxbackupgo.exe
  -authid string
        Authentication ID (PBS Api token)
  -secret string
        Secret for authentication
  -backupdir string
        Backup source directory, must not be symlink. Repeat the flag to back up
        several directories in one run (see "Several directories" below)
  -baseurl string
        Base URL for the proxmox backup server, example: https://192.168.1.10:8007
  -certfingerprint string
        Certificate fingerprint for SSL connection, example: ea:7d:06:f9...
  -datastore string
        Datastore name
  -namespace string
        Namespace (optional)
  -backup-id string
        Backup ID (optional - if not specified, the hostname is used as the default for host-type backups)
  -pxarout string
        Output PXAR archive for debug purposes (optional)
  -backupstream string  NEW
        Filename for stream backup
  -mail-host string
        mail notification system: mail server host(optional)
  -mail-port string
        mail notification system: mail server port(optional)
  -mail-username string
        mail notification system: mail server username(optional)
  -mail-password string
        mail notification system: mail server password(optional)
  -mail-insecure bool
        mail notification system: allow insecure communications(optional)
  -mail-from string
        mail notification system: sender mail(optional)
  -mail-to string
        mail notification system: receiver mail(optional)
-mail-subject-template string
        mail notification system: mail subject template(optional)
  -mail-body-template string
        mail notification system: mail body template(optional)
-config string
        Path to JSON config file. If this flag is provided all the others will override the loaded config file

For JSON configuration a JSON example is provided, fill in only the needed fields.

Several directories in one run

Repeat -backupdir to back up more than one directory with a single command:

proxmoxbackupgo.exe -baseurl "https://yourpbshost:8007" -certfingerprint pbsfingerprint -authid "user@realm!apiid" -secret "apisecret" -datastore "datastorename" -backupdir "C:\Data" -backupdir "D:\Photos"

Each directory is backed up as its own backup group, with the backup id _ (the same ids the GUI uses; -backup-id defaults to the hostname). Retention, pruning and restore therefore treat every directory as an independent series. A directory that fails does not stop the others, and the exit code is 1 if any of them failed. -pxarout cannot be combined with several directories, and two directories that would end up with the same backup id are rejected before anything is uploaded.

In a JSON config file use "backupdirs": ["C:\\Data", "D:\\Photos"]. The single "backupdir" field keeps working and can be combined with "backupdirs".

Encryption works the same way as for a single directory: -keyfile (and -keyfile-passphrase, or the interactive prompt) is read once, and every directory's backup group is encrypted with that key.

Note on mail templating: Go's templating engine is used for mail subjects and bodies, please refer to the documentation for the syntax. The following variables are available for templating:

• .NewChunks: number of new chunks created
• .ReusedChunks: number of chunks reused
• .Datastore: datastore name
• .Error: error message if any
• .Hostname: hostname of the machine
• .StartTime: time the backup started
• .EndTime: time the backup ended
• .Duration: duration of the backup
• .FromattedDuration: formatted duration of the backup
• .Success: a boolean telling whether the backup was successful
• .Status: string representation of the backup status [SUCCESS, FAILURE]

Stream Backup

This allows backing up a stream instead of a PXAR, allowing endless possibilities. For example you can invoke:

mysqldump yourdatabase | ./proxmoxbackupgo -backupstream yourdatabase.sql [other options]

This allows leveraging buzhash for dedup even when using tar for example, or the sql dump itself. And if someone wants to attempt it, it should be possible with some hack to pipe the DISM command to generate a WIM image to this and have a full host backup.

Known Issues

Windows Defender antimalware being active will slow the backup down up to 25% of attainable speed.

~~There's as of now no mechanism to prevent two instances being launched at the same time which will screw up VSS and backup~~ If you use the Windows planning utility it should theoretically prevent two instances starting at the same time when originating from the same job.

📋 Prerequisites

• Windows 10/11 (64-bit)
• Administrator rights (for VSS snapshots)
• Network access to a Proxmox Backup Server
• Linux works too, especially for development

🔨 Building from source

Prerequisites

• Go 1.22 or later
• Node.js 20 or later
• Wails CLI: go install github.com/wailsapp/wails/v2/cmd/wails@latest

GUI

cd gui
npm install --prefix frontend
wails build      # or: wails dev  (hot reload)

Full project (Makefile)

make install-deps   # install Wails CLI + frontend dependencies
make                # build everything (CLI + GUI + Service)

Artifacts are placed in the dist/ directory. See make help for all targets (cli, gui, service, test, lint, security-check, release...).

🔧 Advanced use & guides

Multi-PBS (multiple PBS servers)

Configure several PBS servers and pick the target per backup (e.g. C:\Users → fast SSD PBS daily, C:\ → big-data PBS weekly, plus a DR server).

• User guide — adding/testing servers, default server, FAQ and troubleshooting.
• Implementation guide — data model, automatic migration from single-PBS config, backend API methods.

Clonezilla live ISO (bare-metal restore)

The rescue workflow is built by patching a stock Clonezilla Live ISO with the pbsnbd / machinebackup binaries plus a pbs-nbd entry in the Clonezilla main menu (boots from CD, USB via dd, and UEFI):

./patch-clonezilla.sh \
  -o clonezilla-live-patched.iso \
  clonezilla-live-3.3.3-15-amd64.iso \
  ./build/pbsnbd ./build/machinebackup \
  ./clonezilla-patch/ocs-pbs-nbd

Full details (why a full ISO rebuild instead of an in-place swap, prerequisites, menu flow, verification) in PATCH-CLONEZILLA.md.

Building the Windows GUI

Docker (recommended, especially when building on Linux). The one-command script builds a ProxmoxBackupClientGO.exe with proper WebView2 support, using a disposable golang container (installs mingw + Wails, builds the frontend, runs wails build):

./build_gui_windows_docker.sh

Native Windows (Chocolatey). See BUILD.md for the complete Windows toolchain setup:

choco install go
choco install mingw
then, in a non-elevated shell:
build.bat          # GUI
build_cli.bat      # CLI

Feature status, changelog & internal docs

• FEATURES_STATUS.md — per-feature status matrix (implemented / tested / roadmap).
• CHANGELOG.md — per-version change history.
• TODO.md — open roadmap and ideas.
• RELEASE_NOTES.md — stable product state and available builds.
• MSI_UNINSTALL_TEST.md — MSI uninstall dialog (keep/delete configuration) and its test plan.
• FIXES_SUMMARY.md — GUI fix notes (directory vs machine-backup mode switching).

🌐 Tech Support in Italy

Being said that the project and ALL its contributions will remain forever public and licensed under GPLv3 license, main sponsor of this project and also of the latest machine backup features, E.T.I. Srl ( https://etitech.net ) can provide, to who needs it, support for Proxmox deployments in general and specifically Windows backup tools.

There will never be a "community" & "enterprise" different edition, solely tech support will be an independent service. Any customization that you are going to ask, even if development may be paid, will be released as GPLv3 like the whole project is.

🖥️ GUI attribution

The Proxmox Backup Client GUI is based on the Nimbus Backup GUI, developed and maintained by RDEM Systems.

The GUI (originally a fork of this project) has been merged back into this repository: the entire codebase, including the GUI and all its features, remains open-source under the GPLv3 license. RDEM Systems sponsors the GUI development and provides commercial support for it.

⚠️ Warning

This software is provided "as is". Although we aim for reliability, we decline any responsibility for loss of or damage to data. Always test your backups and verify restoration before relying on them in production.

The software is still alpha quality and we take no responsibility for any kind of damage or data loss, even of source files.

📄 License

GPLv3 — see the LICENSE file.

🏷️ Branding

Every contributor who has contributed at least 5 commits that add functionality or fixes, has the right to have their branding data added for commercial use.

The only conditions are that the company that the branding points to is not running any of the following:

• Malware campaigns
• Businesses promoting war (this applies to any country, including western ones)
• Scams
• Data theft
• Child trafficking
• Violence
• Discrimination
• Drugs
• Any activity generally recognized as illegal

The GPLv3 license remains active, and you will still be free to fork the project and build your own executables.

🤝 Contribute

The GUI is now fully implemented, but contributions are still welcome, especially:

1. Encryption support (still missing)
2. Physical-to-virtual (P2V) migration, restoring a bare-metal backup into a virtual machine (still incomplete)
3. Async upload / multicore upload of chunks (multicore compression is already implemented for machine backup)
4. Proxmox side patch to add another kind of entry to pxar format with Windows security descriptors in it
5. Support for Windows symlinks
6. Anything interesting you can come up with :)

About Proxmox Backup Client GO contributors

Proxmox Backup Client GO contributors develop and maintain this project. The software relies on the NTP/NTS infrastructure and the 11 public NTS servers listed in the community reference.

© 2024-2026 Proxmox Backup Client GO Contributors and RDEM Systems.