Hi Edward,
We have this state saved in the XML created at "C:\Users\USER\AppData\Local\MapInfo\MapInfo\Professional\1600" by the name "MapInfoPro.RibbonState.EN.xml" where EN is for the English language MapInfo Pro.
If you have any xml for the docking state and the ribbon state, at the same location, you can delete that and then the fresh one will save your state.
Regards,
Shweta