Hello
A year ago I installed the paid version of eM Client and at the time I imported my e-mails and Outlook Office 365 folders.
After a year, now I want to delete everything I imported before and do a new import of Outlook Office 365, since I’ve created a lot of new folders.
Please inform the procedure.
Idacil
Note: I used the Google translator to create this message from Portuguese.
Google Translator did an excellent job! 
If you want to completely delete the eM Client database, close eM Client and delete the C:\Users\username\AppData\Roaming\eM Client folder. As this will completely delete everything, make a backup first using Menu > File > Backup.
If you want to keep your settings, templates etc., you can export them before deleting the database using Menu > File > Export > Export settings to .xml file. You can import them back at a later time using Menu > File > Import > eM Client Settings.
Thank you Gary.
There was a question:
My current e-mail application is Outlook Office 365. To import to eM Client, I found only the Microsoft Outlook and Microsoft Outlook Express options.
In my case, which of these options should I use?
Idacil
I am not familiar with Outlook 365, but I would assume it is the Microsoft Outlook option.
If that doesn’t work, then if the account is setup as IMAP you don’t need to import the messages. Just setup the same account in eM Client and it will sync with the server. Your contacts and calendar may have to be exported from MS Outlook and imported to eM Client depending on how they are setup in MS Outlook.