The workbench now uses several submodules.
Installation of workbenches with submodules is not fully supported by Addon Manager.
If the Addon manager has been used in the past a directory OpenDesign will have been created in
FreeCAD's Mod directory, this needs to be removed/deleted otherwise FreeCAD is likely to find out of date
OpenStudio workbench options/facilities.
Until the Addon Manager is updated to full support submodules, the workbench must be manually installed
see the README