Downtime Posted on 8th November 20157th November 2023 by ThePD (The Project Definition) Downtime is a period of time when a computer, machine, or system, etc. is out of action or unavailable for used. (Opposite of the Uptime) Related Definitions in the Project: The Computer Technology Click to share on Twitter (Opens in new window)Click to share on Facebook (Opens in new window)Click to share on LinkedIn (Opens in new window) Related Posted in Science and tagged computer. ThePD (The Project Definition) ThePD has been developing the Preferred Project Definitions based on the actual project execution and operation experiences and knowledge with the Project Language, and sharing with you daily basis.