Summary of "ReactOS: Open Source Windows OS"

Overview

Video demo and review by ExplainingComputers, walking through ReactOS v0.4.15 (released March 2025).
ReactOS is an open‑source reimplementation of the Windows NT family, aiming to run Windows applications and drivers without any Microsoft code via clean‑room reverse engineering.

Goal: binary/application and driver compatibility with Windows NT, with a focus on older/classic 32‑bit Windows applications.
Legal approach: entirely original code through clean‑room reverse engineering.
Architecture and builds:
- 32‑bit builds are the mainstream public downloads and the recommended channel for general testing.
- 64‑bit builds exist but are experimental; they currently lack a compatibility layer to run 32‑bit Windows software (no WoW64 support).
v0.4.15 notable improvements:
- Plug‑and‑play subsystem rewrite
- Audio support improvements
- Memory management and cache control updates
- Registry healing/caching
- Security enhancements
- System tools and accessories improvements
- Shell refinements
Status: still alpha. Considerable progress compared with 2018, but incomplete and can be unstable in some areas.

Official downloads are available from the ReactOS project site, with links to SourceForge and nightly builds.
Available images include live CD images suitable for USB boot and boot/install images.
Live images are useful for testing on real hardware but compatibility is limited; ReactOS maintains a list of known‑compatible systems.

Works better on older or lower‑spec hardware; many modern Intel systems may fail to boot the live USB.
The project provides a hardware compatibility webpage (mostly older devices).
Recommendation: use 32‑bit builds for general testing; 64‑bit builds are for experienced testers only.

Creating a live USB:
- The reviewer used BalenaEtcher to write the Live CD image to a USB stick.
Virtual machine recommended for fuller testing; the reviewer demonstrated an install in VirtualBox.
- VirtualBox notes: some versions (6.1.44 → 7.0.14) have known issues; the reviewer used 7.0.16+ successfully.
- Recommended VM configuration:
  - 1 CPU core (ReactOS recommendation)
  - Up to 4 GB RAM (32‑bit limits)
  - Small virtual disk (10 GB used in the demo)
- Simplified install steps shown:
  1. Boot the ISO
  2. Format and install
  3. Remove the ISO on reboot
  4. Complete setup (user name, password, appearance)
- VirtualBox tips:
  - Increase display scaling (e.g., 200%) for readability in video demonstrations.
  - Install VirtualBox Guest Additions for correct display resizing and improved integration.
The reviewer demonstrated mounting ISO files inside the VM to install Windows applications (for example, Microsoft Office XP).

Bundled applications include:
- A basic web browser (“Wine Internet Explorer” using shared resources with Wine)
- Utilities: Notepad, Paint, WordPad
- Games: Solitaire
- Applications Manager: category catalog for easy installs
Applications tested by the reviewer:
- Microsoft Office XP: installed successfully; Word, Excel, and PowerPoint worked. Access produced errors when creating a blank database.
- Adobe Audition 1.5: installed and played audio successfully, demonstrating the audio subsystem functioning.
- Blender (an early Linux/graphics port listed under Graphics): an early build ran but showed graphics errors.
- Web browsing: simple pages load in the bundled browser; complex sites (e.g., YouTube) do not render properly.
Summary: application support is promising for many 32‑bit Windows desktop apps but is not yet comprehensive.

Stability has improved relative to earlier versions; the reviewer did not see crashes during many app installs in this session.
Remaining instability:
- Heavy crashes occurred when attempting to install a tablet driver and during device manager exploration.
- Driver model and hardware handling remain fragile.
- Graphics and some driver support are limited; expect gaps and instability, especially with newer hardware or complex drivers.

ReactOS shows significant progress and potential as a niche OS for running legacy Windows apps on open‑source software.
Best current use cases:
- In virtual machines on modern hosts
- On older, compatible hardware for testing
Not yet ready to replace a primary OS.
Development trajectory is encouraging, and further improvements are expected as the project matures.

Creating a ReactOS live USB with Etcher
Booting live images on real hardware and checking the compatibility list
Installing ReactOS in VirtualBox (VM creation, recommended settings, format/install sequence)
Installing VirtualBox Guest Additions for better display integration
Mounting ISOs and installing Windows applications (Office XP, Adobe Audition, Blender)
Using the built‑in Applications Manager to install apps

ExplainingComputers (video presenter / host)
ReactOS project (official website / SourceForge / nightly builds)
Wine project (shared resources; Wine Internet Explorer browser)
Tools & platforms referenced: BalenaEtcher, VirtualBox (and Guest Additions), SourceForge, Microsoft Office XP, Adobe Audition, Blender