I'm having a similar issue. I went through a nether portal using Windows 10 Edition and it got stuck "Building terrain". When I killed the process and restarted Minecraft I tried to log back into the realm, but it always hangs at "Building terrain", which means I can no longer log into the realm.
Jeff the Sloth
I'm having a similar issue. I went through a nether portal using Windows 10 Edition and it got stuck "Building terrain". When I killed the process and restarted Minecraft I tried to log back into the realm, but it always hangs at "Building terrain", which means I can no longer log into the realm.