Microsoft has also integrated project Spartan with this new build. In this preview, Microsoft said, Issues that are fixed in this new build:
The issue from Build 10041 for when the Photos app on your PC crashes when you tap on the circular icon at the top left to view the photo you just took has been fixed now. You no longer will have issues where windows open on your desktop are accidentally visible behind the Start Screen, Task View, Snap Assist, and when rearranging windows in Tablet Mode. No longer getting stuck when you manually lock your PC (Windows Key + L) during the initial out-of-box experience.
Some issues which users will continue to face in this build:
After logging in, you may see a blue screen instead of your desktop. To work around this issue, lock your PC (with the hardware button or by pressing the Windows Key + L) and try logging in again. You can also try Ctrl + Shift + Esc to open Task Manager. Indexing of new email in Outlook is not working, so search results will be limited to when the last index was built. If you have Virtual Machines hosted in Hyper-V on your PC running Windows 10, you will want to move to the Slow ring and wait for the next build as this build breaks the ability to run VMs. There are 2 issues using Visual Studio 2015 preview on this build:The emulators will not boot and you won’t be able to deploy a Windows Universal app to the Mobile emulator. The XAML designer in VS and Blend will crash when opened.If you are a developer using these tools today to develop Windows Universal apps and need this functionality to work – Microsoft recommends switching to the Slow ring until they release a patch to fix these issues.
Download Windows 10 Technical Preview ISO from here Note: Windows 10 Technical Preview Build 10049 is in its beta program. You will have to signup and agree to Windows Insider Program before downloading. Resource : Microsoft Blog.