So I ran into an issue during a conversion process moving some clients to Exchange where it would throw an error saying “too many Exchange accounts already exist; Please add the account as POP/IMAP”. Upon looking it up, I found that it is supposed to do this after 10, but it was doing this sometimes while adding the second account!
Run => regedit
Create a new entry called:
1 2 3 4
DWORD: MaxNumExchange Outlook 2010 values: a number between 1 and 15 Outlook 2013 values: a number between 1 and 9999 Outlook 2016 values: a number between 1 and 9999 # I usually just set this to 20.
Try adding the account again.