Following instructions this is what I see In left panel with Orcon provider:
e-mail address: my e-mail address
Description: my e-mail address again
Password 11 characters
Use with: Mail & Notes
With iCloud account:
I see several apps with tick boxes; Those ticked are:
iCloud, Mail, Contacts, Calenders,Safari, Notes, Keychain,
I have now pinpointed the problem as being the main IN box. Mail does not crash if I do not click on the In box. However I can click either of my mail accounts that appear as sub folders of the IN box without Mail quitting but the messages do not appear.
I can access all my mailboxes stored on my iMac and send mail provided I do not attempt to open the IN box.