Occasionally during a windows update (most recently in the case of updating to Windows 10) files that ProCal uses can be overwritten and deleted.

One such file is the driver for the licence dongle.

To re-install the dongle driver, download the installation file here : http://transmille.net/ProCal/setupdrv%20Net.exe

Please Note : This is NOT a substitute for a full installation of ProCal on new computers, this utility is designed to add/replace files that may have been modified during updates to your computer.