Does anyone know what to do if I'm trying to download a previous years turbo tax and it is giving me a error code for the license number

From where are you downloading the file? Is this from the TurboTax web site?

https://accounts-tax.intuit.com/app/turbotaxdesktop

@donnadonaldson 

AND...what year?

If 2019 desktop software, TTX isn't allowing that to be installed anymore, as they shut down support after 3 years.   

Years prior to 2019 can be installed on Windows, since there is no license code needed....but no updates, nor states are available, so their utility may be impacted by what the exact version is, for the installation file you have.