Check out the steps to troubleshoot
Yahoo mail not updating on Mac device. Follow the guidelines as start by running the application and enter Yahoo account credentials to resolve Yahoo mail not working on Mac device. After that, select MBOX format or required format from Export Format. Now, choose advance settings option to apply the settings on Yahoo mail. Lastly, click on start backup option to start with the fixing process. It is advisable to follow the steps properly to troubleshoot Yahoo mail not updating on Mac device.