[quote=“lehang, post:16, topic:48205, full:true”]
Why i can’t install it?
[/quote] Assuming you mean Round Corners ??
Download its RBZ [from the EWH or SketchUcation > PluginsStore] and use SketchUp’s built-in installer on that file…
Window > Extensions Manager > Install Extension [red button]
[OR if older than v2017 Preferences > Extensions > Install… [gray button]]
BUT note that most of Fredo’s tools also need his LibFredo installing - so also download the RBZ for that and install it.
Restart SketchUp after the installation to ensure everything gets synced.
Check it’s loaded in the Extensions list - if necessary activate it…