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
Navigate to: HKEY_CURRENT_USER\Software\Microsoft\Exchange
Create a new entry called:
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.