: Be aware that Trimble ended support for "Classic Licenses" in 2020. While your 2018 perpetual license should still work, web-based features like the 3D Warehouse
: Ensure your key is specifically for 2018. A key for 2019 (starting with "U") will not work on the 2018 version. Seat Limit sketchup pro 2018 add license key
may no longer be accessible directly within the 2018 interface. SketchUp Community SketchUp Pro 2018 - Add-License : Be aware that Trimble ended support for