A new build of Windows 10 Pro has been leaked online. The Windows 10 Pro Insider Preview Build 10558 was leaked by WZor, the famous Windows leaker. The most prominent new features in Windows 10 Build 10558 is an early version of the Messaging app powered by Skype, Phone app, Skype video app, ability to install app on different drive, and improvement to Microsoft Edge web browser, Settings app and Start menu.

In Edge, Tab Preview is now available by simply hovering the mouse cursor over the tab without having to actually switch tab, and Edge’s Settings flyout menu has been refined. In Start Menu, the context menu (which appears when you right click or long press on a tile) has been updated to make it wider, neater, more organized and now come with integrated icon for the pin and resize options (as a way to demonstrate the size of tile too). More right click context menu options are also added for File Explorer (only on Start Menu) through More menu with access to: “Manage”, “Properties”, “Map network drive”, “Disconnect network drive”, and “Don’t show in this list”.

One of the major feature introduced in Windows 10 Build 10558 is ability to install Windows Store apps on an external storage disk such as SD card, USB flash drive or portable hard disk drive, or other hard disk drive on the computer. The option can be configured in the Settings -> Storage, and is extremely useful for users with tablets or laptops with limited disk space.

Other enhancements include updated icons, Spotlight support in Enterprise and Pro edition, Find My Device feature in case you lost the device, and etc.

With so many enhancements that are expected to roll out to all Windows 10 users in Threshold 2 (TH2) update start to take shape in Windows 10 Build 10558, the leak will grant you early access to the features and functionality. However, the leak is unofficial and install it at your own risk.

Here’s the Windows 10 Build 10558 leak information (search to download the ISO):

BUILD: 10558.0.150928-1738
SIZE: 4,044,433,408 bytes

Update: Windows 10 Build 10565