Download O3O Office

Version 26.8.4 · Windows 10/11 64-bit · released 14 September 2026 · release notes

Download O3O-Office-26.8.4-win64.msi

System requirements

  • Windows 10 (1809 or later) or Windows 11, 64-bit.
  • 4 GB RAM or more; 2 GB free disk space.
  • No additional runtime required.

Installation

  1. Double-click the .msi file, choose Next and follow the wizard.
  2. After installation O3O Office preloads in the system tray and places four shortcuts on the desktop.
  3. Double-click any .docx/.xlsx/.pptx/.pdf file or open the applications from the Start menu.

Silent installation

msiexec /i "O3O-Office-26.8.4-win64.msi" /qn /norestart ALLUSERS=1

Updates

O3O Office checks for a new version daily and pre-downloads the installer; you can also use Help → Check for updates. Install over the previous version; no uninstall needed.

The installer is not yet code-signed; Windows SmartScreen may ask for confirmation. Choose More info → Run anyway.