Windows Backup Cluster

Open Source GUI Client Antivirus False Positive on Windows Unattended Deployment (Ansible)GUI merged upstream (tizbac)Nimbus Backup 0.4.1: encryption, signing

Windows Backup Cluster

Backup Pricing Model Guide

Open Source GUI Client Antivirus False Positive on Windows Unattended Deployment (Ansible)GUI merged upstream (tizbac)Nimbus Backup 0.4.1: encryption, signing

Case study: first 1 TB prod backup

Proxmox Backup Client for Windows: Free GUI, VSS Snapshots

Download the Proxmox Backup GUI client for Windows and configure backup of your workstation to your NimbusBackup datastore.

Published: March 17, 2026

10 min read

Updated: October 9, 2026

🧪 Version 0.4.1 available (beta)

The Windows GUI client is in advanced beta. Core features (scheduled backups, Windows Service, multi-PBS, in-client restore, unattended deployment) work on our test infrastructure. Version 0.4.1 (9 October 2026) brings client-side encryption developed by Tiziano Bacocco, compatible with proxmox-backup-client, and signed binaries; whole-machine backup with physical disk selection, new in 0.4.0, is still in beta. What changes in 0.4.1.

💬 Your feedback shapes what comes next! Test and share your experience on GitHub Issues.

✅ Version 0.4.1 status

Functional ✅

✅ VSS-consistent snapshots + native PBS deduplication
✅ Two modes: folders and whole machine / disk
✅ Snapshot browsing & restore inside the client
✅ Windows service + scheduled backups (survives sleep/reboot)
✅ Multi-PBS with independent per-server scheduling
✅ File-driven unattended deployment (Ansible)
✅ Login with a PBS API token or username/password — new in 0.4
✅ Cancel a running backup — new in 0.4
✅ Interface in 5 languages (FR, EN, IT, DE, PL), email notifications
✅ Client-side encryption compatible with proxmox-backup-client, developed by Tiziano Bacocco — new in 0.4.1
✅ Signed binaries (Authenticode, RDEM SYSTEMS) — new in 0.4.1
✅ Several folders backed up in parallel, one VSS snapshot per backup — new in 0.4.1

In progress 🔧

🔧 SmartScreen reputation: RDEM SYSTEMS shows as a verified publisher; the SmartScreen warning may remain until reputation is established, see antivirus false positive
🔧 Whole-machine backup with disk selection: still in beta

💡 Your feedback helps us prioritize improvements!

📊 Real-world numbers: see our 1 TB Windows case study →

First full production backup of an 876 GB Windows bare metal server to PBS: 20h30 transfer, 75 % deduplicated chunks, 57 % end-to-end savings. On the 2^nd daily run: 99.97 % dedup, just 1.73 GB uploaded over the wire — ~310× less traffic for the same 876 GB protected.

Read the full case study

The Need: Backing Up Windows Machines

At RDEM Systems, we offer NimbusBackup, an offsite backup service based on Proxmox Backup Server. You do not want to build your own PBS? See offsite Windows backup, with nothing to install on the backup server side.

Our customers back up their Proxmox VMs, Linux servers, and LXC containers seamlessly using PBS native tools.

But one question kept coming back:

"How do I back up my Windows workstations and servers?"

The need is clear: businesses have Windows 10/11 workstations, Windows Server 2019/2022, SQL Server databases, domain controllers...

These machines contain critical data that must be protected just like their virtualized infrastructures.

To protect your Windows workstations and servers without complex infrastructure, a client-server solution like NimbusBackup natively accepts Windows client backups via our open source graphical interface. Operational in less than 15 minutes with API token authentication and native deduplication. Unifies protection of your Linux VMs and Windows machines in a single secure datastore in France. For maximum ransomware protection, our Air Gapped offer adds complete network isolation. We detail below how our open source GUI client finally enables simple and complete backup for the Windows ecosystem.

Typical Use Cases

Workstations (Documents, Desktop, projects)
Windows application servers (databases, files)
Active Directory domain controllers
Windows file servers

On the production side, this client has already cleared a real volume: see our 1 TB Windows case study: 20h30, 75% dedup for raw figures from the first production run (876 GB source, transfer window, ratios). On the prerequisite side, authentication relies on a dedicated PBS token — managing PBS API tokens (creation, revocation, scopes) is documented separately. Note that the NimbusBackup GUI client is only one of three ingestion methods into PBS (alongside Proxmox VE integration and the Gateway for NAS): to compare them, follow our guide to choosing your backup method.

The Challenge: Nothing Simple

Proxmox Backup Server is primarily designed for the Proxmox and Linux ecosystem.

There is no official Windows client.

The command-line proxmox-backup-client is only available on Linux. For your Linux servers, from Debian to Alpine, here is how to install proxmox-backup-client on Linux.

For Windows, the options are limited:

❌ No official client: no Windows support from Proxmox
❌ No graphical interface: must use third-party solutions
❌ Incomplete third-party clients: abandoned or unmaintained projects
❌ Complex scripts: require advanced technical skills

We explored the alternatives: third-party clients, wrappers, PowerShell scripts...

Nothing satisfactory.

Existing solutions were either too complex, abandoned, or closed-source.

The main problem:

To offer NimbusBackup to our customers with Windows machines, we had to provide them with a simple, reliable, and graphical solution.

Which Proxmox Backup client should you use?

Three clients can write to a Proxmox Backup Server today. They don't compete: each one fits a different operating system and a different need.

Client	Operating systems	Interface	Best for
proxmox-backup-client official Proxmox client, written in Rust	Linux only: Debian and Ubuntu officially; RHEL, Rocky, Alma, Fedora, Arch and Alpine through our unofficial repository (RPM, Arch, Alpine)	Command line	Linux servers — see the Linux installation guide
proxmoxbackupclient_go original project by Tiziano Bacocco (tizbac), written in Go	Windows, Linux, macOS	Command line (our GUI has been in the main branch since September 2026, not yet in a release)	Custom scripts and integrations — upstream releases (v1.1.3 as of May 2, 2026)
NimbusBackup our fork of tizbac's client, with a GUI	Windows 10/11, Windows Server 2019/2022	Graphical interface, Windows service, file-based deployment	Windows workstations and servers — the subject of this guide

Our GUI joined the original project's main branch in September 2026 (not yet in an upstream release): read how we contributed the Windows GUI upstream to tizbac.

The Solution: Developing an Open Source GUI

Rather than waiting for a solution to appear, we decided to act.

We decided to contribute to the community by developing our own Windows graphical interface for Proxmox Backup Server.

Finding the Most Promising Client

We explored several existing open source projects.

We found proxmoxbackupclient_go developed by Tiziano Bacocco (@tizbac).

This Go client had several advantages:

✅ Cross-platform: works on Windows, Linux and macOS
✅ Performant: written in Go, native compilation
✅ Functional: backup and restore already implemented
✅ Open source: code available and modifiable
❌ Command line: no graphical interface

The base was solid. We just needed to add a GUI.

Developing the Interface

We developed a graphical interface using modern technologies:

Wails v2 for the desktop application (Go + HTML/CSS/JS)
React for the user interface
Tailwind CSS for styling

The goal was to create an intuitive and accessible interface for Windows users unfamiliar with the command line.

An Open Source Project

We made our work available to everyone under GPLv3 license. The source code is published on GitHub.

Community contributions are welcome: bug reports, feature suggestions, code improvements... The GUI itself has joined the original project: see our Windows GUI contribution to tizbac.

Our other contributions: an unofficial proxmox-backup-client repository for RHEL, Rocky, Alma, Fedora, Arch and Alpine, and a guide to install Proxmox Backup Client on another Linux distribution.

View on GitHub

The Result: A Functional Windows GUI Client

After several weeks of development, we have a functional Windows client for Proxmox Backup Server.

The client is operational for real backups, but some advanced features are still under development.

An error? See the Windows client messages, with their cause and fix.

Open Source Windows Client

Graphical interface to backup your Windows files and folders to Proxmox Backup Server

📦 Version 0.4.1 (October 2026) - proxmox-backup-client-compatible encryption, signed binaries

Upgrading from 0.4.0: the MSI upgrades in place and the configuration is kept. What is new is detailed in the 0.4.1 article.

Upgrading from 0.3.0: the MSI upgrades in place (same Windows service, same executable). On first start, the configuration, scheduled jobs, job history and API token are copied from C:\ProgramData\NimbusBackup to C:\ProgramData\ProxmoxBackupClient: once, never overwriting a file already there, and the old folder is kept. Backups taken with 0.3.0 can still be restored to their original location.

💬 Your feedback matters! Test and share your experience to help us prioritize what comes next.

NimbusBackup.exe (Standalone) - Stable ✅

✅ Portable, no installation
✅ Manual backups work perfectly
✅ Ideal for testing or one-time backups
⚠️ Not restarted after reboot

📦 NimbusBackup.msi (Installer with Service) - since v0.2.24

Windows Service auto-start
Admin privileges (VSS guaranteed)
Scheduled backups survive reboot
Anti-conflict protection (v0.2.24)
Clean uninstall via Control Panel

✅ Status: working on our test fleet

Scheduled backups, the Windows Service and multi-PBS work on our test fleet. Our tests did not catch everything: 0.4.1 fixes disk backups, which all failed at the finalize step, a scheduled job even showing as successful with no snapshot on the PBS (#9), and the service, which ignored the PBS server selected for a folder backup and used the default one.

💡 Recommendation: Test on non-critical systems and share feedback on GitHub Issues

Compatible Windows 10/11 (64-bit)

Based on proxmoxbackupclient_go

Official download: binaries signed by RDEM SYSTEMS (Authenticode) since 0.4.1, SHA-256 checksums published with every release. The only official source of the binaries is github.com/rdemsystems/NimbusBackupClient. Check the signature and checksum

Quick Installation

Download the latest version from GitHub Releases
Download NimbusBackup.exe (portable) or NimbusBackup.msi (installer)
.exe version: Run directly | .msi version: Install via Windows wizard
Create your API token from the member portal
Import your JSON configuration into the client
Select folders to backup and start your first backup!

Open Source Project

This client is open source and available on GitHub. Contributions welcome!

View source code on GitHub

🤖 Unattended deployment (new in 0.3)

Since 0.3, installation and configuration are fully file-driven — built for Ansible. Two paths (command line for pure IaC, or a service driven by a single config.json carrying connection + schedule), reliable exit codes and idempotent reconciliation. Ideal for rolling out Windows backup across a whole fleet.

Read the guide: unattended deployment with Ansible

To protect your Windows Server 2019/2022, SQL Server databases, and Windows 10/11 workstations without complex infrastructure, a client-server solution like NimbusBackup natively accepts backups from Windows clients via our open source graphical interface. Operational in less than 15 minutes with API token authentication and native deduplication. Unifies protection of your Linux VMs and Windows machines in a single secure datastore. For maximum ransomware protection, our Air Gapped offering adds complete network isolation. We detail below how our open source GUI client finally enables simple and complete backup for the Windows ecosystem.

Next Steps

Download the client

Click the download button and extract the ZIP archive.

Import configuration

Copy the JSON above and import it into the GUI client.

Start your backup

Select your folders and start your first backup.

Step-by-Step Guide

How to backup your Windows machine with the GUI client

Step 1: Download and Run as Administrator

🔐 Signed binaries since 0.4.1

NimbusBackup.exe, the service and the NimbusBackup.msi installer are signed (Authenticode, certificate issued to RDEM SYSTEMS). RDEM SYSTEMS shows as a verified publisher; the SmartScreen warning may remain until reputation is established.

If Windows still blocks the file:

Browser: Click "..." → "Keep file"
Windows: Right-click → Properties → ✅ Unblock
SmartScreen: check that the publisher is RDEM SYSTEMS, then click "More info", then "Run anyway"

Why this warning, and how to check the file's signature and hash →

Executable file after extraction

proxmox-backup-gui.exe file in Windows Explorer

Run as Administrator

⚠️ Why administrator?

Access to protected system folders (C:\Users\...\AppData, etc.)
VSS support (Volume Shadow Copy) for consistent backups
Read locked files used by other applications

💡 Optional if you only backup your personal documents.

Step 2: Configure Your Token

If you don't have an API token yet, follow our guide:Create an API token on NimbusBackup.

Configuration interface - Step 1

Configuration interface with URL, Auth ID, Secret fields

Validated configuration

Complete configuration with tested connection

✅ Once the connection is successfully tested, your configuration is ready.

Step 3: Start Your Backup

Backup launch interface

Backup interface with Start Backup button and options

🚀 Deduplication in action: PBS stores identical data only once. Your incremental backups are ultra-fast and space-efficient!

Step 4: Restore Files

Restore is built into the client

Since 0.3, snapshot browsing and restore happen directly in the client, with fast search (reads the pcat1catalog, no full-archive scan).

TheRDEM Systems member portalremains available to restore individual files and full snapshots.

🌐 Multi-PBS: Multiple Backup Destinations

Configure multiple PBS servers with independent schedules

Enhanced 3-2-1 strategy:

Primary PBS in datacenter (e.g., NimbusBackup)
Secondary PBS on-premise or another cloud
Different schedules per destination
Maximum disaster protection - Learn about air-gapped strategies

Your PBS already receives the Windows backups? The missing piece of the 3-2-1 rule is the offsite copy: check our offsite backup pricing (from €12/TB/month, EU hosting, no egress fees).

Geographic redundancy

Data on 2+ sites

Flexible strategy

Different schedules per destination

🧪 Working on our infrastructure with 2 simultaneous PBS. 0.4.1 fixes the service, which ignored the PBS server selected for a folder backup and used the default one.

🤖 Smart Auto-split (v0.2.25 - To Test)

Automatically splits large backups into optimal jobs

Automatic detection: Backup > 100GB → automatic split
Bin-packing algorithm: Smart folder distribution
Optimal jobs: ~100GB max per job for maximum reliability

🚧 Status: To validate in production

Feature implemented and ready. We're looking for users to test on large volumes (500GB+) and share feedback.

💬 Have large volumes to backup? Test auto-split and share on GitHub Issues!

Roadmap

Development status and upcoming features

✅ Shipped (v0.2.24 → v0.4.1)

Encryption, signed binaries, parallel backups (v0.4.1) - ✅ Released

Client-side encryption compatible with proxmox-backup-client, developed by Tiziano Bacocco in the original project, with a paper key and key import from a QR code. Signed binaries and MSI (Authenticode, RDEM SYSTEMS). Several folders backed up in parallel, one VSS snapshot for a whole multi-folder backup, exclusions in the command line. Fixes: a busy VSS no longer deletes every shadow copy on the machine, disk backups (#9), selected PBS server ignored by the service, progress in service mode (#2). Details.

Reunited with the original project (v0.4.0) - ✅ Released

Nimbus Backup is rebuilt on the code base shared with Tiziano Bacocco's project, which merged our GUI. PBS username/password login, cancel a running backup, 5-language interface, whole-machine backup with physical disk selection, automatic configuration folder migration. Reliability: the command line now returns an error code on failure, and the CSRF token no longer appears in logs.

Unattended deployment and in-client restore (v0.3.0) - ✅ Released

Install and configure entirely through files (Ansible), browse and restore snapshots in the client, bilingual FR/EN interface, TLS hardening (certificate pinning).

Windows Service with scheduled backups (v0.2.24) - ✅ Working

The Windows Service works on our test infrastructure, with anti-conflict protection. 0.4.1 fixes scheduled disk backups, which failed at the finalize step and could show as successful with no snapshot (#9). Feedback welcome!

Multi-PBS with separate jobs (v0.2.x) - ✅ Working

Configure 2+ PBS servers with independent schedules. Enhanced 3-2-1 strategy, geographic redundancy. 0.4.1 fixes the service, which ignored the PBS server selected for a folder backup and used the default one.

🚧 Implemented - Field Validation Needed (v0.2.25)

Smart auto-split (v0.2.25) - 🚧 To test in production

Backups > 100GB are automatically split into optimal jobs. Bin-packing algorithm, fully transparent. Implemented, seeking testers for large volumes!

🔜 Next steps

Planned features for upcoming versions:

A shared codebase with the original project

The GUI joined tizbac's project in September 2026; the goal is a single shared codebase.

SmartScreen reputation

The binaries are signed since 0.4.1. SmartScreen reputation then builds up as downloads accumulate; later versions signed with the same identity can inherit it.

📅 No release date announced: new versions are published on GitHub Releases.

📢 Your feedback drives our priorities.

💬 Test and share on GitHub Issues

Contribute

Your feedback is essential to stabilize the client

💌 Thank you for your messages

Since going live, we've received several emails from users — and honestly, it's genuinely heartening to see the project is appreciated and useful to you. Thank you! This is exactly the kind of feedback that keeps us going toward a stable release.

Your feedback is essential to stabilize the client:

🐛 Bugs

Report issues encountered

💬 Feedback

Share your experience

⭐ Success stories

Help us validate!

📖 Source code

RDEM Systems fork

Testing priorities:

✅ Windows Service with scheduled backups
✅ Multi-PBS (2+ servers)
🚧 Auto-split on large volumes (500GB+)

Each feedback brings us closer to a stable release! 🚀

📊 Case study: first 1 TB production backup

The GUI client just completed its first full production backup on a Windows bare metal server of around 1 TB: 20h30 of continuous transfer, 75% deduplicated chunks, 57% end-to-end savings. Raw figures and an honest reading (including what we cannot yet claim).

Read the full case study

Business case summary: 1 TB Windows backup (FR)

Frequently asked questions

Yes, the PBS GUI client for Windows works on all Windows editions: Windows 10 Home, Windows 10 Pro, Windows 11 Home, Windows 11 Pro, and Windows Server 2019/2022. No special license is required.

Windows Server 2019 and 2022 are fully compatible with our PBS GUI client. Download the client, create an API token from the member portal, import your configuration and select the folders to backup. VSS (Volume Shadow Copy) support ensures consistent backups even with open files. SQL Server databases can be protected via VSS or file-level backup.

Yes. You can backup SQL Server databases via VSS (Volume Shadow Copy) or by backing up the .mdf and .ldf database files. The client supports both approaches. For production databases, we recommend using VSS for consistent online backups.

The current client focuses on graphical interface (GUI) to simplify configuration. For automated backups or Windows Server Core installations, you can use the official proxmox-backup-client CLI available from Proxmox. Our GUI client is ideal for Windows workstations and servers with desktop experience.

Our PBS GUI client works identically on Windows 10/11 (workstation) and Windows Server 2019/2022. The main difference lies in your needs: Windows Server typically requires System State backup, Active Directory, SQL Server or IIS configuration protection. Our client covers all scenarios with VSS support and flexible folder selection.

Yes. Since version 0.3, snapshot browsing and restore happen directly in the GUI client, with fast search via the pcat1 catalog. The Proxmox Backup Server web portal also remains available to download individual files and full snapshots.

Technical Guide

Create a PBS API Token

Complete guide to create and manage your authentication tokens on NimbusBackup.