Outlook

I would assume you launched Outlook 365 already and it created the initial folder.

If Outlook 365 is running, close it. Go the location I mentioned above (posted again, next).

/Users/your_account/Library/Group Containers/UBF8T346G9.Office

Open the folder UBF8T346G9.Office. Put these two items in the trash.

Outlook (a folder)

OutlookProfile.plist

Launch Outlook 365 and immediately go to the import menu.

Contact Microsoft for assistance with their products.

You have to import it. Launch Outlook in Office 365. From the top menu bar, choose File > Import.

The box that appears automatically assumes Office 2011 data. Click Continue. Assuming you haven't moved or deleted Office 2011's Outlook data from its standard location, the top radio button will be selected. Click Continue.

All of your Outlook 2011 data will be imported to Outlook 365. This includes all emails, contacts and other data. Typically, the only thing you need to supply after that is your email account password to send and receive emails.

Once done, the old data is no longer used for anything. You can either deleted the old 2011 Main Identity folder, or copy it off to an external drive as a legacy backup. Everything will now be located here:

/Users/your_account/Library/Group Containers/UBF8T346G9.Office