Microsoft introduced a new feature into Windows 10 that automatically updates your default printer to the last printer that was used.
This is known to cause issues with ProCal and ProCal-Track as after printing a label using a label printer Windows is defaulting to the label printer for all other print outs.
To disable this behaviour in Windows, click on the Start Menu and then click on the Gear Icon to open the settings menu.
In the settings menu, navigate to Devices.
Then click on Printers and Scanners.
Scroll to the bottom of this list and untick the option labelled 'Let Windows manage my default printer'.
The default printer will now no longer be switched when a label is printed.