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Installation and requirements

Install the O&O Defrag package that matches your Windows architecture and licensed edition. The product provides x64 and ARM64 packages for Professional and Server editions.

Before you install​

  1. Check your Windows version and system type in Settings → System → About.
  2. Obtain the appropriate installer from O&O Software.
  3. Sign in with an account that can approve administrator elevation.
  4. Close other applications and finish any active drive maintenance.
  5. Keep your license information available if you are installing the full version.

Use Professional Edition for supported Windows desktop systems and the appropriate Server Edition on Windows Server. Check the installer and the current product support information for the exact operating-system compatibility of your build.

The computer must meet the requirements of its Windows version and have enough free space for installation. Preparing the optional Windows RE optimization environment requires additional space on the system drive and a usable recovery environment; see boot-time optimization.

Install​

  1. Run the downloaded setup program.
  2. Approve the Windows administrator prompt.
  3. Read the license agreement and follow the setup pages.
  4. Complete installation. Restart the computer if setup requests it.
  5. Open O&O Defrag from the Start menu.

Setup installs the application and the background O&O Defrag Agent service. The interface connects to that service to analyze drives, perform optimization, and manage scheduled jobs. Keep both components at the same product version.

If the interface cannot connect, see Agent unavailable.

Drives you can work with​

Select drives exposed by the agent in Drive Optimization. A drive needs to be available to Windows, accessible, and eligible for the chosen operation. A mapped network share is not equivalent to a local volume. Removable and external drives may need to be enabled in Optimization settings.

For RAID, USB enclosures, virtual disks, and encrypted volumes, check the detected media type before selecting a method. Use Drive detection only when you know Windows has reported the wrong type.

Update or remove the application​

Use the product's update mechanism or an appropriate newer installer; see Licensing and updates. Finish active jobs before maintenance of the installation.

To uninstall, open Windows Settings → Apps, find your O&O Defrag edition, and choose Uninstall. Follow the uninstaller and restart if requested. Removing the application is different from disabling background optimization. To retain the program while stopping automatic maintenance, use Automatic optimization.