Windows 10 build 9841 (fbl release)

Windows 10 build 9841 (with a build tag of 9841.fbl release.140912-1613) is a pre-release build of the Microsoft Windows 10 operating system. The build was demonstrated by Microsoft on 2014-09-30 and released as a technical preview on 2014-10-01.

This build is the first publicly available build of Windows 10. It was demoed on 2014-09-30 at a closed press conference and released to the public the next day. It replaces the start screen with the start menu.

To run this build your system requires at least: 1 GHz or faster processor, 1 GB or more RAM (for x86) or 2 GB or more (for x64), at least 16 GB of HD space, and a DirectX 9 graphics device with a WDDM driver. The reporting feature also requires a Microsoft account.

Features
This build is quite rough, both in terms of functionality and UX. However, this is to be expected considering the earliness of Windows 10 at this stage.

VirtualBox Installation
If you're installing on VirtualBox, you must change the host PC's time to the BIOS date time listed (2014-09-13) even if you turned off the time sync and set the BIOS date for the virtual machine, otherwise after the hardware setup it will automatically adjust to the current time and will hang during the login and render the virtual machine unbootable upon reboot.