Frequently asked questions

A free online defrag simulator

Remember watching your disk’s scattered blocks fall into place? JustDefrag recreates that little ritual with Windows 98 Disk Defragmenter, the Windows XP disk usage bars, and a classic MS-DOS Microsoft Defrag screen. Pick a look, watch the animation, and take a moment to unwind.

Does this defragment my computer?

No. This is a visual simulation for nostalgia and relaxation. The disk map is generated in browser memory; JustDefrag never reads or changes your files.

How do I use it?

The simulation starts automatically. Switch between Windows 98, Windows XP and MS-DOS without losing progress. Both Windows views have pause, stop and restart controls. XP also shows a volume analysis and report. In DOS mode, click the screen and press Space to pause or resume, Escape to stop, or Enter to restart a stopped session. Turn on Endless for a fresh disk after each session, go fullscreen, or mute the hard-drive sounds. Sound is enabled by default; if your browser blocks autoplay, it starts after your first click, tap or key press. Share sends a link to your selected interface. If your device requests reduced motion, the simulation starts paused.

Do I need to download anything?

No download, installation or account is needed. All three interfaces run in your browser and are free to use. Read about JustDefrag.