I have been experiencing the same thing on Windows 10 edition. I've tried several times and in various ways.
Download world, play locally for a bit, attempt to replace Realm, exports successful, get the "An error has occurred".
I'd just restore from a backup but I've made some changes I really want to keep, so my options are basically to cancel the Realm until this is resolved.
I even attempted to sign up for another account by using the "Play on Realms" button from my local game. However, the Realm gets seeded with a random world, not the world I selected. Then, attempting the replace the world with the newly create Realm also fails. I'm beyond frustrated.
Now I have two realms - with worlds I don't want to play on. Go figure.
I have been experiencing the same thing on Windows 10 edition. I've tried several times and in various ways.
Download world, play locally for a bit, attempt to replace Realm, exports successful, get the "An error has occurred".
I'd just restore from a backup but I've made some changes I really want to keep, so my options are basically to cancel the Realm until this is resolved.
I even attempted to sign up for another account by using the "Play on Realms" button from my local game. However, the Realm gets seeded with a random world, not the world I selected. Then, attempting the replace the world with the newly create Realm also fails. I'm beyond frustrated.
Now I have two realms - with worlds I don't want to play on. Go figure.