Had the Config Tool issuing an error popup stating that the there is an issue with the XML when attempting to save a configuration on MacOS Mojave:

1. launch Config Tool
2. edit / enter a configuration and upload on device
3. select Configuration / Save, popup comes up, I entered a simple name like "SS316L.fox"
4. hit save
   A popup comes up reporting an error while writing the XML.
   Hope this help, keep up with the amazing good work.
   Francesco