Until recently I had my @msn.com email as the primary account name and a secondary email on a Office365 domain.   I could happily login to Office.com (msn stream) and into Office365.com (work email stream) separately and with using different passwords and keeping the email boxes separate.  Last week I changed the Primary Account Alias to my Office365 domain.   At which point I can no longer login to Office.com as it creates the error message " You're currently signed in with an Office 365 email account, which can't be used with Outlook.com. Please click here to sign out of your Office 365 account, .....".  Clicking 'here doesnt resolve it.

So on trying to reverse the assignment of my primary account email alias back to @msn.com , the microsoft account now returns " you cant use @msn.com in you Microsoft email address, please try a different email address.

Note :  the reason why I am keen to keep the email logins separate is that when I have tried to include the @msn.com email into my Office365 email , it tends to bring all the emails into the same inbox rather than keeping the email streams as separate entities ...any help please?