The first thing to check is the physical connection of the TS1.
This is done viewing the System Report.
- Click on the Apple logo in the upper left corner then select About This MAC.
- Select System Report.
- In the under Hardware section, click on USB.
- Expand the USB Device Tree and locate C-Pen TS1.
If C-Pen TS1 exist, then the physical connection is OK.
If the C-Pen TS1 does not exist there is a physical connection problem. Try to connect the TS1 to another USB port and/or test it on another computer to verify it.
NOTE: System Report\Hardware\USB list will have to be refreshed at each new connection. Exit it an re-enter the USB Device Tree list.
Assuming that the C-Pen TS1 does exist in the USB Device Tree, then the problem is caused by software.
- Kill VDCAssistant (if running). To do so, open Terminal and run command sudo killall VDCAssistant (provide password when prompted). Check this article and view this video for more details if required.
- Make an SMC Reset.