When the build 9926 was released for Windows Insiders, there were some known issues like start menu fails to launch and other, Microsoft has released an update KB3034229 or the Windows 10 Technical Preview January Update Rollup for Windows 10 build 9926 to address these, this update provides a collection of reliability and performance improvements.

Read: Windows 10 build 9926 lets you Set File Explorer to open ‘This PC’ as default Folder

According to the associated Microsoft Knowledge Base article, this update includes the following improvements.

  • Reliability improvements to prevent some system crashes in explorer.exe
  • Fixes an issue that could cause a deleted app to be unintentionally reinstalled
  • Increased power efficiency to extend battery life
  • Reliability improvements for virtual machine live migrations
  • Performance improvements for Internet Explorer
  • Fixes an issue that could cause pending Windows Updates to be incorrectly reported in the update history
  • Fixes an issue that could cause the Start Menu to be improperly registered and fail to launch
  • Fixes an issue that could cause random pixilation on the screen when using Remote Desktop Client

KB3034229 update

 How to remove the Windows Rollback entry on Boot Menu added by Windows 10 Build 9926?

To check if it is already installed on your computer, open the new Settings app, visit  Update and Recovery section. 

Link: KB3034229