Today i upgraded Windows 10 to Insider Preview 17672.1000 (rs_prerelease) from the fast Ring.

Currently i’m got some troubles with starting that apps:

• xb.exe (eXtra Buttons)
• GreenshotOCRCommand.exe
• TuneupUI.exe (Avast Cleanup)
• AvastUI.exe (Avast Antivirus)
• jetbrains-toolbox.exe
• OneDrive.exe / OneDriveSetup.exe
• Facebook App
• XING App

If you use one of them, and thinking about upgrading them, so better wait until the next build.

More on: https://aka.ms/AA1edf9

Edit: After a complete delete from all Avast Tools the Update works perfectly.