If it’s 0.27.0 or earlier, you can just back up license.json from %NUITRACK_HOME%/nuitrack/data (for example, rename it).
If it’s 28.0.0, you have to back up license.json, run the Nuitrack activation tool and enter your trial key (you can download Nuitrack Trial at our website or generate the trial key in your Nuitrack account).
Also please advise what errors do you receive after the activation? That’s really strange because the only difference between Nuitrack Trial and Pro is a time limit and a generated license.json file.
I was using 0.27.0 with my pro license when I was receiving errors in Visual Studio. It’s strange since my license.json was no including in my nuitrack directory but Visual Studio was still claiming I had an invalid license.
I continued receiving errors when upgrading to 0.28.0.
However, I followed this link that helped resolve my license issue:
Using this new license process, I can now develop in Visual Studio with the pro license without any errors.