Error Message: 'GridItemThemeKeyExtension_DefaultBackgroundColor_OneStreamBlue' resource not found.

Hi molly_lvc 
Please could you contact support directly for that one. It seems that the error in with some Dlls or DevExpress Theme. This seems to be called at the startup.
Without going into detail on why/what/how (which are usually our favorite questions 😁), I am pretty sure there is nothing we can do about it as it is a backend issue. Maybe a simple restart will solve it. If not, contact the support.

Have a good week end,