@gingras2009 

You can update your QB Desktop 2020 to R17 as the latest version. You can also use your QB Desktop 2020 with the non subscription license for good to manage multi company files. What do you mean by "it won’t let me add a new company I am handling"?

One critical question. Can you access CAMPS as Primary Contact and find your license code there?

https://camps.intuit.com