Panic set in. Error 6 often pointed to a mismatch between the and the version of the FlexLM server installed. If the server didn't "handshake" with the software, the CAD window would never open.
The SSQ Error 6 is an activation error that occurs when SolidWorks 2018 is unable to connect to the SolidWorks activation server. This error typically manifests as a pop-up message with the following text: "SolidWorks 2018 Activator SSQ Error 6: Unable to activate SolidWorks. Please try again." solidworks 2018 activator ssq error 6
If you see keys related to SolidWorks or SSQ, right-click and delete them. Panic set in