[[:Microsoft]] **WinPad** (also known as **Handheld Windows**) is an **un-released** mobile [[:operating system]] by [[:Microsoft]], and is confirmed to be the earliest development of the mobile operating system made by [[:Microsoft]] that **pre-dates** [[Windows CE]]. The system was initially **based on** [[Windows 3.1]] and later ported from **pre-release** builds of [[Windows 95]] (then known as **Microsoft Chicago**). **WinPad-compatible handhelds** would synchronize between desktops (using the **Switchboard**) running [[Windows 95]], and allow **e-mail**, **faxing**, **file transfer**, and **task management** on the **mobile device**.

An **SDK** and debug build **exists** for [[Windows 3.1]] (and can run standalone in Standard Mode), while the [[Windows 95]] port is newer but more limited. Development on **WinPad was dropped before the RTM** release of [[Windows 95]]. The user interface and architecture later influenced the development of **Microsoft Pegasus**, which became [[Windows CE]].