Extensions won't install (RBZ files). Solution: 2018 requires the extension to be signed or manually installed. Go to Window > Extension Manager and select "Install Extension." If it fails, unzip the RBZ and place files in the SketchUp 2018/ShippedExtensions folder manually.
The power of SketchUp Pro 2018 lies in its extension ecosystem. Unlike later versions that broke certain Ruby API scripts, 2018 supports a massive library of plugins. Here are the "must-install" extensions:
This is the biggest hurdle. Trimble typically only supports the last three versions of SketchUp for direct 3D Warehouse access. To get models into 2018 now, you often have to download them as .collada files or use a "down-saver" extension.
