New build of Windows 10 Mobile brings fixes and some massive bugs

Build 10512 isn't much for whiz-bang new features. Microsoft focused instead on minor fixes and improvements, including a general improvement in overall stability. More specifically, the update also fixes an issue that caused apps installed on a phone's SD card to stop working after a reboot. Notifications for text messages and Windows 10's bandwidth-tracking Data Sense feature will also show up more reliably.

Text input improvements were another area of focus for the release. People writing in Latvian and Chinese will have an enhanced experience. The Swype-esque Shape Writing feature that lets users type by dragging a finger across the keyboard is now more likely to suggest common words over names of contacts on the phone.

While the new build brings some welcome new fixes, there are also some killer bugs included with the latest release. First and foremost, the Mobile Hotspot functionality that allows users to share their phone's Internet connection with other devices doesn't work in this build. Users who pinned a "large number of tiles" to their phone's Start screen may get their device stuck in a state where it just shows a loading screen. In the event that happens, users will have to reset the device or roll it back to Windows Phone 8.1.

That's not all -- the Movies & TV app won't work in the current build, and some apps will fail to update through the store. (The latter problem can be fixed by uninstalling the app and re-installing it.)

Right now, build 10512 is only available to members of the Windows Insider Program's Fast ring who have opted into more cutting edge updates at the expense of encountering bugs. Users who only opted into the Slow ring will remain on build 10166 for now.

The update doesn't include support for any new phones, but that may change soon. Joe Belfiore, a corporate vice president in Microsoft's Windows and Devices group, said last month that Microsoft plans to open up the Windows Insider Program in China by releasing a version of Windows 10 for the Xiaomi Mi4.

That's an interesting move, since the Mi4 is currently only available with Android installed. Expanding its mobile operating system to popular phones in China like the Mi4 could spur some growth for Microsoft at a time when the company's mobile business has failed to gain traction with users.

Microsoft had been providing mobile build updates at a more rapid clip in June, but held back on releasing multiple new versions in July as the company polished and shipped the desktop and tablet version of Windows 10. With that launch in the rear-view mirror, Microsoft Vice President Gabe Aul said in a blog post that users should expect to see more updates to the mobile version of Windows 10, which is slated for a consumer release this fall.

It could be a while before that launch actually translates to end users receiving the update, even for Lumia phones that Microsoft controls. Carriers have to approve the final update before it can roll out to users, which has held back Windows Phone updates for months in the past.