Try this: Go to your "Studio One" folder. (AKA "User Data Location" via the Studio One "Options/Preferences" menu in the Location tab.) If you use the Options/Preference to find that folder, be sure to close S1 BEFORE using the steps below!
With Studio One CLOSED:
- Find the "Macros" folder in the Studio One folder you found above.
- Locate the "CommandBar.xml" file and rename it to something else.
- Restart S1 and it should rebuild the default macro toolbar.
Let us know how that goes.