I'm also on Windows 10, and I can also successfully replace a realm world with a vanilla world with no add-ons, but when trying to replace a realm world with the Star Wars Mash-Up I experience failure during 'Initializing Upload' with the ever-useful 'An error occurred' message.
Changing the http lib settings made no difference.
FYI the skins / resource pack was applied and available in Creative but the world template / behavioural pack had not been applied.
Kr33p3rz72
Experienced the same symptoms as Matthew Bettenberg
I'm also on Windows 10, and I can also successfully replace a realm world with a vanilla world with no add-ons, but when trying to replace a realm world with the Star Wars Mash-Up I experience failure during 'Initializing Upload' with the ever-useful 'An error occurred' message.
Changing the http lib settings made no difference.
FYI the skins / resource pack was applied and available in Creative but the world template / behavioural pack had not been applied.