The workaround is to save the project (including an optimization window that is some number of hours) with the 'export' button, open the project.json in the folder you just saved with a text editor, and change the “optimizationHorizonNum” field in the file to the number of hours you want the optimization window to be. Save this project.json, then load it into the GUI using the 'Use Existing Analysis' button on the landing page. Run the project with the play button - it should run with your hour-based optimization window!

[DER-VET_GUI_Error_Hourly_Opt](//muut.com/u/der-vet/s3/:der-vet:Mvqk:dervet_gui_error_hourly_opt.png.jpg)