This is still NOT "Solved" but has been an issue for years. If you're using QB desktop and you have multiple email accounts in Outlook (i.e. a work and a personal account) you can NOT change the default email account for invoicing. It doesn't matter what the Outlook default account is. What does matter is the email account that is the Outlook default "data file". By the thread it's obvious that this has been a problem for a while. The Outlook default data file is what controls your Outlook to-do bar and calendar. You could change your default Outlook data file to the work account and your QB invoices would send correctly but that's not an acceptable solution for changing Quickbooks default email account since you'll mess up your Outlook calendar and To-Do bar. You could "send" the invoice and quickly change it while it's in your outbox to another "From" email account (you'd have to do that for every invoice you send which again is not a good solution) Quickbooks still needs to fix their "default email" problem if they really care about us sending emails from the correct business account instead of our personal account.