Windows 8 build 7878

Windows 8 build 7878 is a build of Windows 8. Seven screenshots of this build were included with the original upload of build 7746. It was later shared on the BetaWiki Discord server on 4 June 2021.

New features and changes

 * The File History feature, originally known as History Vault, has been introduced in this build.
 * The modern setup client first introduced in build 7814 now includes a progress bar and has the ability to go online to check for updates.

Immersive features

 * The Start screen tiles are now colored, and the Metro Horizon has been removed, although its resources are still present in.
 * Right-clicking on a tile now shows a menu with several options.
 * Pattern logon is available if you set  in   to 1, however there's no option to use it on the login screen.
 * A new OOBE has been introduced.
 * A new AutoPlay dialog has been added, which is just the exact same as Windows 7 but longer.

Installation
The messages shown when the Setup is starting or restarting the computer are cut off.

Out-of-box experience
Attempting to select a network type will result in a driver unload bugcheck. To work around this issue, remove or disable any network adapters before booting into OOBE.

General

 * If using VMware Workstation versions 15.x or above, attempting to restart or shutdown in this build will cause a softlock. To fix this, use the Power menu from the VM section.
 * Certain visual elements in select MMC snap-ins (such as Services) may use the Wingdings font.
 * An unassigned file association error may occur if certain options in the Start tile drop-down menu are selected.

Arial
This build uses the Arial font for the title bar and watermark because of a typo in the  and   files.

Aero
This build appears to have a slightly broken Windows Aero theme, with only the top portion of the window frame using the blur effect, leaving the side borders transparent.

Personalization
Changing personalization options may occasionally crash File Explorer. This is caused by  and can be fixed by replacing the file with a copy from build 7875.

Language Bar
The new language bar is mostly broken in this build and only works on rare occasions. It may occasionally spawn an empty, non-functional button between the notification area and the current date/time.

Desktop Window Manager
The Windows Basic and the High Contrast themes do not properly render due to the enforcement of the DWM Aero theme.