BUG: cannot move messages to root mailfolder in namespace "There can be only one namespace with inbox=yes"

[Marc Roos]

I can only move messages to a root namespace folder when specifying 
inbox=yes. That is strange because it is not even the inbox. I don't 
even get why it is not by default possible, maybe bug there?

You have made the mistake of overloading the use of a parameter 
inbox=yes (or not creating a parameter to tell folder can be used to 
move messages to), there is indeed only one folder that gets incoming 
messages delivered to, and that is the inbox=yes. You should have 
created a 2nd parameter specifying if a folder should be allowed to 
store mail. 

(I have been running this dovecot server for 20 years or so, and I am 
really surprised about still running into issues on such basic things as 
trying to put folders onto different storage. Not to mention the lack of 
help you can get here. Is there some roadmap, features implementation 
overview available? Can you make public issues on github?)