Look at the path in Options > Locations > User Data. Inside that folder path you should see a \Songs folder, a \Macros folder (if the Macro toolbar is installed) and other things. You should see a commandbar.xml file there. Close Studio One first and delete it.
If Studio One does successfully launch despite the error, and assuming that the Macro Toolbar is installed, go to Studio One > Macro Organizer to open that window and there is a direct link to the Macros folder at the bottom of that window. Same as above, close Studio One and delete the commandbar.xml to see if it stops the error.
P.S. If for some reason you are running Apple desktop sync on Windows, try disabling it to see if you stop getting the macro errors on load.