Quickbooks

Quickbooks and Thunderbird

Quickbooks only supports a few email clients, so if you are to install a 2nd one alongside an existing setup (Outlook), do not choose Thunderbird. Use something obscure. If you choose Thunderbird, when you already have Outlook setup, it is possible that Thunderbird will take over the email settings, and if you try to uninstall TB, everything in QB breaks. So stick with Claws or something less known, and don't mess with Thunderbird and QB, unless its the only email program you plan to use.