Thunderbird is an open source email client which is a free alternative to Outlook. AccountEdge will work with Outlook and Thunderbird and will send through either of them when they are set up as your default email client.

In order you configure Thunderbird to be used with AccountEdge, you may need to do the following below. The following videos goes through the steps of setting up Thunderbird.

Setting Up and Using Thunderbird Video

Configuring Thunderbird and Disabling MAPI-EX if Needed

Step 1 - Ensure Thunderbird is Your Default Email Client 
In order to use Thunderbird for Windows and AccountEdge, you need to first ensure that Thunderbird is your default email client. AccountEdge will only send email through your systems default email client. You can set this default within the Thunderbird Options window. Under Options within Advanced you'll find a Check Now button that will check to see if this is set correctly.

Step 2 - If you have Outlook Also Installed 
If you have Outlook or another email client installed, you may need to deselect Outlook from being your default mail client within Outlook. For some reason even if you set the default to be Thunderbird, it may not reset the default within Outlook and your system will continue to not find Thunderbird as the default.

Step 3 - Disable MAPI-EX 
If you receive an error message "MapiEX could not open the message store or outbox" you may need to manually disable Mapi-EX with use with AccountEdge. We have included a file in a directory in your AccountEdge installation, where when moved to a new location, AccountEdge will know to disable MAPI-EX when sending email from AccountEdge.

For 2017 version and all versions after: Move the MapiEX Disable.txt file from C:\AccountEdgePro2017\MAPIEX Disabler folder to the C:\AccountEdgePro2017 folder.

Essentially you are moving this file from a sub folder directly into the folder that contains the AccountEdge.exe so that AccountEdge can find this file.

Step 4 - Run Thunderbird as Administrator 
Depending on your computers user account and the rights that your user has, you may need to ensure that you are launching Thunderbird as an Administrator. If you are unable to send email, try exiting Thunderbird and then find your Mozilla Thunderbird directory in your Program Files directory and then right mouse click the Thunderbird.exe application and select Run as Administrator.

Additional help troubleshooting email issues