- Oven temperature too high. Excess heat causes exterior cracking. Bake at lower temp. - Baking too long. Overbaking dries out exterior faster than interior. Reduce time. - High humidity. Moist oven air causes uneven drying. Bake on low humidity days. - Egg whites under-beaten. Weak meringue structure cracks more easily. Whip whites to stiff peaks. - Sugar added too early. Sugar needs to dissolve fully before baking. Add only at stiff peak stage. - Cooling too quickly. Slow cooling helps prevent cracks. Cool in turned off oven. - Baking was too crowded. Overcrowding prevents even airflow. Space meringues further apart.