To authorize , you need a serial number and an authorization code, which were historically sent via email upon purchase. SketchUp 2016 used a "Classic" perpetual license system, which is distinct from the modern sign-in subscription model. How to Authorize SketchUp 2016
to have the details emailed to the address associated with the purchase. Check Inside the App sketchup 2016 serial number and authorization code
The SketchUp 2016 Serial Number Hunt: Why It’s a Digital Dead End (And What Actually Works) SketchUp Pro 2016 To authorize , you need
If you have your serial number but lost the authorization code, use the SketchUp License Manager to have the details resent to the registered email address. Check a Currently Licensed Machine: Windows: Go to Help > License > License Info . Mac: Go to SketchUp > License > License Info . Activation Steps Title: The SketchUp 2016 Serial Number Hunt: Why
If you need professional features (like Solid Tools or LayOut), you can download the latest version of SketchUp Pro and use a 30-day free trial.
with the subject line containing "SketchUp Pro License Information". Use the License Manager