If you have the 10074 build of the Windows 10 Insider Preview, you can expect to download a new patch via Windows Update sometime later today. The update is to fix an issue with "Project Spartan", the new web browser than has since been renamed as Microsoft Edge.
While the official Microsoft support site does not yet have a listing for this patch, Windows Insider leader Gabriel Aul mentioned the update on his Twitter account. He stated the patch is to resolve an issue that was causing Project Spartan to crash when launched.
A few day ago, Microsoft released an update for Windows 10 build 10074 that included several other bug fixes, along with adding support for the Dolby Digital Plus codec. You can check out what's new in that build in our detailed guide to version 10074.
Source: Gabriel Aul (Twitter)