I'm really sorry, but if you downloaded SwitchMuiMaster in the latest 24 hours, please download it again from its new address:
> Download SwitchMuiMaster.lha from Paolobesser.it (207 k)
I've found too late a stupid bug that prevented SwitchMuiMaster from correctly restoring muimaster.library v19 after using of v41. I apologize for the mistake and for any issue it might cause. The version in the Archives will be updated soon.