eM Client "tried to access nonexistent namespace" for the Deleted-folder

Whenever eM Client opens up, it pops up an error message saying the folder for deleted elements could not be created. “(Client tried to access nonexistant namespace. Mailbox name should probably prefixed with INBOX.) (0.001 0.000 secs). )”

It also shows an Error sign behind the “Deleted”-Folder. 

The text in quotation marks (") is original, the rest is translated by myself. So the wording there might not be the exact same used in English.

Thanks in advance!

EDIT: Also please note that the E-Mail I use is not the E-Mail affected by the error.

You did not say what version of eM Client you are using, nor who the email provider is, which makes it difficult to know if this is a known issue or not.

But probably the easiest solution may be to remove the affected account from eM Client, then add it again.

Oh, sorry.

The version is 7.2.36775.0 for Windows 8.

The E-Mail provider is freenet.

If removing the account then adding it again does not work, you can try uninstalling, then download and install 7.2.35595 from the Release History.