There has been an error reading data for calendar: %1$S. It has been placed in read-only mode, since changes to this calendar will likely result in data-loss.  You may change this setting by choosing 'Edit Calendar'.
Bu gwall wrth ddarllen data ar gyfer y calendr: %1$S. Mae wedi'i osod ym modd darllen yn unig, gan fod newidiadau i'r calendr yn debygol o arwain at golli data.  Mae modd newid y gosodiad drwy ddewis 'Golygu Calendr'.