If the software is already installed and working on an old computer, go to Help > License (Windows) or SketchUp > License (Mac) to view your active serial number. Steps to Authorize SketchUp Pro 2017
Requires a paid "Classic License" (serial number and authorization code) for commercial use. Sketchup 2017 License Key And Authorization Number
This is the free version for personal use. It does not require a license key. After a 30-day trial of the "Pro" features, you simply click an "I Agree" button to continue using the free version indefinitely. Troubleshooting Common Issues If the software is already installed and working
Copy and paste your Serial Number and Authorization Code exactly as they appear in your email. It does not require a license key
This often happens if you try to use a 2017 license on a 2018 or newer version. Licenses are version-specific.
If you purchased a "Classic License" for SketchUp Pro 2017, your credentials were sent to the email address used during the original purchase.