I have the same problem. When alpha 20 experimental was launched I could generate new worlds. But at a certain point after an update (don't know which one) it became impossible to generate a new world. When the generation reaches Writing Data Map Complete stays there eternally.
NullReferenceException: Object reference not set to an instance of an object error prevents joining the server
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I have the same problem. When alpha 20 experimental was launched I could generate new worlds. But at a certain point after an update (don't know which one) it became impossible to generate a new world. When the generation reaches Writing Data Map Complete stays there eternally.