Microsoft released Windows 10 Mobile build 10536.1004 just a few days ago to Fast Ring insiders, which is the first preview build that Microsoft has made available since Aug. 12.
The Windows 10 Mobile build was delayed for a few days as Microsoft caught a bug, preventing the build to be released on Sept. 11. Nevertheless, users that were anticipating the build's release expected several features and improvements such as the addition of one-handed mode, a Photos app update and several fixes for a variety of issues.
However, it appears that the delay in the release of the Windows 10 Mobile build was not able to fix everything, as there have been reports of the update breaking the smartphone upon its installation.
The issue is happening due to a glitch on the device checking system of the software that allows unsupported smartphones to download and install the Windows 10 Mobile build. Because the update is only meant to be used with certain devices, non-supported mobile phones that install the operating system stop working.
The glitch is causing the users of these non-supported smartphones to see and download the Windows 10 Mobile build, when they should not be doing so. Microsoft is now working to release a fix for the operating system to prevent even more devices from being broken.
According to Gabriel Aul, the corporate vice president of the Engineering Systems team in Microsoft's Windows and Devices Group, smartphones broken due to the installation of the Windows 10 Mobile build can only be fixed by reflashing the device back to its factory image, which is a process that most users are not knowledgeable of doing, in addition to factory images not being readily accessible.
— Gabriel Aul (@GabeAul) September 15, 2015
Aul, however, assured through his tweets that Microsoft is working on the problem, as well as providing options for affected users on how to recover their devices.
This is a high priority for us to solve and have a team dedicated to it. We will let you know as soon as we have info on recovery. — Gabriel Aul (@GabeAul) September 17, 2015