The microstructures of BME-X7R ceramics have been investigated by imaging and analytical TEM, By varying the sintering conditions (pressing, sintering temperature and atmosphere), the microstructure changes drastically, and dislocation loops can be observed. These defects most probably are caused by an ordering of oxygen vacancies in the lattice, and the density appears to be correlated to the oxygen partial pressure applied during the reoxidation step. For pressed and unpressed ceramic foils, a model for different sintering behaviors according to liquid-phase assistance is given that is based on a kinetically determined microstructure rather than thermodynamic equilibrium.