Dont worry, this sounds complicated but its just a simple browser setting.

You can usually find JavaScript options in your browsers Settings, Preferences or Internet Options menu.

Change From Pop To Imap In Outlook How To Enable JavaScript

Here are the instructions how to enable JavaScript in your web browser.

Your Sent Items as well as any additional folders you may have created will not be downloaded because POP only sees the Inbox folder on the server.

To move items in these folders, youll need to select the messages inside instead of the folder itself.

Click on the first message in the list, then press ControlA on your keyboard to Select All messages in the folder.

To move (dont copy) your Calendar items, it is best that you first switch your view to a List View.

This way you can see all your Calendar items at once and use the same MoveCopy methods as you did for your email.

After importing the rules, you must re-select the folder for any rule with the move to folder action.

You can set this on the Data Files tab, by the location for your POP mailbox (PST file) and then clicking on Set as Default.

After the restart, go back to the Account Settings dialog and remove the IMAP account.

How To Change From Pop To Imap In Outlook For Mac