Nimbus Backup — Windows client for Proxmox Backup Server

🇬🇧 English | 🇫🇷 Français

Nimbus Backup is an open-source (GPL-3.0) Windows backup client for Proxmox Backup Server (PBS). A modern GUI to back up Windows servers and workstations to PBS — VSS-consistent snapshots, scheduled jobs, file and disk modes, snapshot browsing and restore, multi-PBS support, and a Windows service. Looking for offsite, immutable PBS storage without self-hosting? See the managed service below.

Keywords: proxmox backup client windows · PBS client · Windows VSS backup · offsite immutable backup · proxmox backup server GUI.

📦 Download

👉 Download the latest release

⚠️ Windows says "virus detected" (e.g. Trojan:Win32/Sabsik.FL.A!ml) or shows a SmartScreen warning? This is a known false positive for Go/Wails applications — it is not a virus. The !ml suffix means it comes from a machine-learning model that flags unsigned, low-prevalence executables. Read why this happens and how to verify the download.

🔎 Verify any download

Every release ships SHA-256 checksums and a signed build-provenance attestation (cryptographic proof the binary was produced by this repo's CI, from a specific commit):

Get-FileHash .\NimbusBackup.exe -Algorithm SHA256   # compare against SHA256SUMS.txt
gh attestation verify .\NimbusBackup.exe --repo rdemsystems/NimbusBackupClient

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

ℹ️ Code signing: Windows binaries are not yet Authenticode-signed, which is what triggers the SmartScreen / !ml warnings above. This project is developed on volunteered time; a paid Authenticode certificate isn't funded out of pocket yet. We applied for a free OSS certificate via the SignPath Foundation but have had no reply. A signing certificate will be purchased as soon as the project sustains it commercially — either through managed PBS revenue or sponsorship. Until then, provenance is established via the build-provenance attestation and checksums above.

☁️ Managed PBS (offsite & immutable)

Don't want to self-host Proxmox Backup Server? Use our fully managed, offsite immutable PBS datastores: 👉 Configure your backup & see pricing

• ✅ From €12/TB/month
• ✅ 1 TB free trial
• ✅ A ready-made offsite target for your PBS — air-gapped, immutable datastores
• ✅ NimbusBackup — Managed PBS hosting in France

📚 Documentation

• Complete Proxmox Backup guide — PBS deployment best practices (🇬🇧 EN)
• Back up Windows with Proxmox Backup Server — Windows-specific deployment guide (🇬🇧 EN)
• PBS vs Veeam — Proxmox Backup Server comparison (🇬🇧 EN)

✨ Features

GUI interface (recommended)

• 🌍 Multi-language — English & French interface
• User-friendly configuration with connection testing
• Real-time backup progress with speed and ETA
• VSS (Volume Shadow Copy) support for consistent backups
• Multi-folder backup, file and disk modes
• Snapshot browsing, file search (wildcards) and restore
• Multi-PBS server support, certificate fingerprint pinning (TOFU)
• Windows service mode + scheduled backups
• Debug logging for troubleshooting

📸 Screenshots

Multi-PBS server management with status indicators

Easy server configuration with connection testing

Real-time backup progress with ETA and speed

Smart system exclusions (file mode)

When backing up an entire drive (e.g. D:\), Nimbus Backup automatically excludes:

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

Why it matters: a drive may report 1.03 TB used while the real files are ~141 GB. Without exclusions the backup would include VSS snapshots (wasted space and time); with them the backup 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 restore (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

🤖 Unattended deployment (Ansible & IaC)

Nimbus Backup installs and configures entirely from files — no interactive setup. Two paths, both covered by ready-to-use examples in examples/automation/:

• Command line — one JSON file per host carries the whole backup (directorybackup.exe --config file.json); schedule via the Windows Task Scheduler. Reliable exit codes (0 OK, 1 fatal, 2 locked, 3 partial) so your orchestrator detects failures. Best for pure infrastructure-as-code.
• GUI/service (MSI) — a single config.json carries the PBS connection, backup settings and the schedule (scheduled_jobs). Push the file, restart the NimbusBackup service: jobs are reconciled idempotently and nextRun is computed for you. No timestamp math in your Jinja2 template.

📖 Full walkthrough: Automate Windows backup to PBS with Ansible.

🚀 Quick start

1. Download NimbusBackup.exe (or the .msi) from releases
2. Run with administrator privileges (required for VSS)
3. Configure your PBS connection and test it
4. Select directories to back up
5. Start the backup

📋 Requirements

• Windows 10/11 (64-bit)
• Administrator rights (for VSS snapshots)
• Network access to a Proxmox Backup Server

🔨 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

Build

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

📝 Source project

This project is a fork of tizbac/proxmoxbackupclient_go, enhanced with a modern GUI and additional features for Windows users.

Original: Proxmox Backup Client in Go · Author: Tiziano Bacocco (tizbac) · License: GPLv3

Feature	tizbac/proxmoxbackupclient_go	NimbusBackupClient (this fork)
CLI mode	✅	✅
Wails GUI	❌	✅
Multi-language (FR/EN)	❌	✅
Real-time progress	❌	✅
Smart system exclusions	❌	✅
Multi-PBS support	❌	✅
CI/CD pipelines	❌	✅
Comprehensive tests	❌	✅

⚠️ Disclaimer

This software is provided as-is. While we strive for reliability, we take no responsibility for any data loss or damage. Always test your backups and verify restoration before relying on them in production.

📄 License

GPLv3 — see the LICENSE file.

About RDEM Systems

NimbusBackupClient is developed and maintained by RDEM Systems, a French infrastructure provider specialized in Proxmox VE/PBS managed services and NTP/NTS infrastructure. We operate 11 public NTS servers (live status, also in the community reference), and provide fully managed PBS hosting for users who don't want to self-host.

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