"Special" folders become None

Every once in a while my K-9 client (on Android) decides to forget all the mappings concerning “special” folders I made. So the “Sent”, “Drafts”, “Trash”, etc become None and I lose plenty of messages before realizing what happened. When this occurs, K-9 does not give any warnings: I send or delete a message and K-9 just throws it away. It is the only mail client I use with this weird behaviour.

What am I missing? How am I suppose to configure K-9 in such a way that the configuration is kept whatever happens?

K-9 Mail only changes the mapping automatically in two cases:

  • The value of a special folder is set to automatic in K-9 Mail (that’s the default) and the server changes which folder is associated with a special role. If the server associates no folder with a special role, K-9 Mail will honor that (this is displayed as Automatic (None) in settings).
  • A folder that was manually configured for a special role disappears from the server. In that case K-9 Mail doesn’t try to recreate the folder. It will change the special folder entry to None. If that folder later reappears, K-9 Mail will not remember that it was configured as a special folder.

The server is an institutial Office365.com, that uses localized special folders and does not offer the possibility to change them.

However, there is an event that triggers this forgetting by K-9. Every once in a while, I have to specify again where I want my messages stored. If there is anything I can do to figure out the trigger event, please let me know.