Hello, we are sorry for the inconvenience. It happens only for the polish localization, that’s why it slipped through our testing. Here is a version with the quick fix:
Windows
https://www.emclient.com/dist/v10.3.2097/setup.msi
Mac
https://www.emclient.com/dist/v10.3.2097_Mac/setup.pkg
More permanent solution will be released in the beginning of the next week.