In the case of Windows 10 you should use Mach3 Version R3.043.062 which you can download from
https://www.machsupport.com/downloads-u ... -programs/.
I guess the mach3 license is ok because you wrote that the program works with the selected parallel port. Probably, when updating windows10, there was some error in assigning the right of access in the previous version of Mach3.
As Gerry suggests, you can try a fresh installation of Mach3.
Uninstall the previous version of mach3 and install the version R3.043.062 that runs under Windows 10. Before installing the UC300ETH plugin, copy the license into the mach3 folder and start the program. Mach3 should start as a licensed version. If everything is ok, install the UC300ETH plugin and create a profile for the machine.
Install Mach3, UC300ETH plugins and create profiles by right-clicking on the file and selecting
Run as administrator.
For all applications (plasma and router) except for rotary work,
I use UCCNC. For rotary applications I use Mach3.
Now the test version of UCCNC v1.2108 adds support for rotary axes as well as G93 so I will be able to do rotary jobs from UCCNC.