I have the same issue and this does not solve the problem.
When I restart Quickbooks Desktop there is a window the pops up saying "Sign in to Quickbooks company file successful To open the company file, you need to sign in to your Intuit account.
You're the admin and own/manage this company and its financial actions."
Within that particular box the email address is for the past company owner (my ex-business partner). When I click on continue the next window that opens has the past owners email there and I cannot change it out to a different email.
If I go to CAMPS as the reply suggests, I have no way to log in to make the change because it requires the email address and user id of the past owner. So there is no way for me to update the email address to a new one.
There is no way for me to be able to remove the past email address and update with a new one.
