1. Press the Home button on your iPad and choose Settings.
2. Scroll down and click “Mail, Contacts, Calendars” from the list.
3. Click your email account – it should have an arrow to the right of the email address displayed.
4. Scroll to the end on the settings and click Advanced.
5. Scroll down and tap the empty IMAP Path Prefix.
6. Enter INBOX in capitals, then click ‘Accounts’ at the top left and click ‘Done’ at the top right twice to close the settings.
7. Press the Home button and then re-open Mail.
8. You will now be able to delete or move your emails on your iPad without the error message appearing!