Importing e-mails to the local folder makes them double

I want to import e-mails (eml format) to the Local Folder. The program can import but all e-mails appear doubled. If i delete the folder and repeat importing to the new created, than everthing is tripled and repeating the same steps it copies more and more. Any ideas how to resolve this?

I have solved it by deleting the mail_data.dat file in (C:\Users\Name\AppData\Roaming\eM Client\Local Folders) and importing everything once more. Anyway the program is probably not updating the mail_data file correctly. It needs to be fixed to work properly.