Can't create IMAP-subfolders

When I try to create a subfolder within a existing and empty IMAP-Folder I get an error saying: [CANNOT] Mailbox doesn’t allow inferior mailboxes". This is not completely right. When I log into my webmail I can create new folders and define them not to contain mails but subfolders. In those folders I can create subfolders (which sync correctly to eM Client). To me, the problem seems to be that I can’t tell eM Client that folders are to contain subfolders, not mail.

Is there any way to work round this problem, other than to use my webmail to create folders?

Hi, unfortunately if you’re seeing the “[CANNOT] Mailbox doesn’t allow inferior mailboxes” error it is unfortunately not possible to create subfolders using your setup account in eM Client. This unfortunately seems to be forbidden on the protocol, are you using a Yahoo account with eM client?

Thank you,

No. I’m using an IMAP-account with my own domain, hosted at

Can you please navigate to Tools > Settings > Advanced and enable IMAP logging for the problematic account?

  1. Save the settings
  2. Restart the application
  3. Replicate the issue
    Once the issue reoccurs, please go back to the advanced settings window and submit the logs to us with a reference link to this forum topic for more information about the issue.

Thank you,

Done :slight_smile:

Hi, thank you for the received data, unfortunately the received data confirm my original suspicion, this is unfortunately a server side issue as I previously mentioned, please contact your mail server’s vendor support in order to resolve the issue.

Thank you,


we also have this Problem, but in the Mail Client “Mozilla Thunderbird” theres a Solution for this Problem:

"Select IMAP Account properties -\> server -\> advanced and deselect the "Server supports folders that contain sub-folders and messages" option"

Now you can add a New Folder with the Type “Only Folders”, then you can add another folders into this folder, but it can’t add Emails (You can see 2 of this folders in the Screenshot, the grey ones are the “only contains folders”-folders)

But we want to use the eM Client in our Company, but with this problem, we cant use it…
Is it possible to add this feature to the eM Client? (For Example: New Folder -> Folder contains: only Folders")

Best Regards

Hi Jens, this unfortunately is not an identical issue. This option only allows you to remove sub-folders from Trash when the trash folder has the “server does not allow you to create inferior mailboxes” error, this option in Thunderbird would allow you to remove subfolders. In eM Client removing subfolders from Trash should be possible even in case the error occurs when moving subfolders to the Trash.

"If you try to delete a folder you may get a " Target mailbox doesn’t allow inferior mailboxes " error message. This is because its trying to move a folder with messages in it to the Trash folder on a IMAP server that doesn’t support the idea that folders can contain both messages and a folder." {1}


Its not only to move a subfolder to the Trash…
When the “Server supports folders that contain sub-folders and messages” option is disabled, you have a new option in the “New folder” dialoge:

Sorry, i only got a german screenshot, translation:
Name des Ordners - Name of the Folder
Erstellen als Unterordner von - create as a subfolder of
Nur Ordner - folders only
Nur Nachrichten - messages only

Dieser Server beschränkt Ordner auf zwei spezielle Arten. Der Neue Ordner darf Folgendes enthalten
This server folder limited to two special type of folders. The new folder only contain the following

My Mail-Server provider (same as Glowazowskis,  say that you have to use a “/” behind the folder name, then you can create a “folders only” folder (with other mail clients), but the eM Client shows a error message that “/” is not allowed in the folder name.


Hi Jens, yes you should be able to create a folders only folder, however it is not supported to create folders with a “”, I’ve discussed the issue with the developers and we’ll consider improving this for future release, however this is a very specific feature request and would be very difficult to workaround as the use case does not occur that often.

Thank you,

Hello Paul,
is there any workaround or something that we can create “folders only folders” in the eM Client or we need to wait for a future release?

If the folders only folder is possible, we would buy some licenses…

Regards, Jens

PS: it not the backslash “”, its the normal slash “/”

This is currently not possible, slashes are not allowed in the folder name as that would be pointing out to another folder, which would generate issues for users unaware of this. Allowing to add the slash into the folder name, is not possible.

This would require a special User Interface option, as I mentioned this will be considered, but unfortunately I’m unable to confirm the implementation in future releases.


Are there any News? eM Client 7?
Regards, Jens

No News to this… no change in Em Client 7 Alpha?
Then the Em Client is dead for our company… :frowning:

Hi Jens,
this is not a planned addition to the program.
I’m sorry for the inconvenience.
It might be better to change your server settings to supporting both sub-folders and messages folders.