Photoshop Elements 2018 - Error Launching Default Browser

Photoshop Elements 2018 V16.0 x64 appears to have a problem linking to Firefox 57.0 x6-bit. Selecting Help drop-down menu then any item from 'Photoshop Elements Help' to 'Forum...' results in an error message: There was an error launching the default browser. You may need to re-install the application and Help component. 

Firefox was my default browser. I changed my systems Apps Defaults (under Windows Settings) to another browser (Windows e) and it resolved the problem.