If you are attempting to use Split Tunneling via macOS, you may encounter an issue with the Split Tunnel System Extension being automatically disabled by default, which will cause the feature not to work as expected.
In order for Split Tunneling to work, the macOS system itself needs to give the Windscribe app permission to monitor and manipulate traffic, otherwise Windscribe cannot properly perform the split tunneling functions. This is just the macOS system ensuring that you explicitly hand over that permission. A malicious app trying to get your network traffic wouldn't be able to because of this security prompt notifying you of its actions.
When the split tunnel extension is used for the first time in macOS, the OS pops up a one-time prompt indicating the user should allow the extension in system settings.
This can sometimes be missed if the dialog is just closed, and not actioned at that time. Whatever the case, here are the instructions on how to enable this feature if needed (scroll down for instructions on older macOS versions).
Command + Space
, type "System Settings", press Enter).Further Reading
What is Split Tunneling and how to use it
Why doesn't the Windscribe iOS app have Split Tunneling?