How to install SketchUp extensions — the 2026 guide

There are exactly three ways to get an extension into SketchUp, and one of them fails silently often enough to fill forum pages. This guide covers all three — Extension Warehouse, the .rbz file, and a manual copy — on Windows and macOS, for SketchUp 2024 through 2026, plus the short list of reasons an extension installs fine and still refuses to appear.

Route 1 — Extension Warehouse, from inside SketchUp

1. In SketchUp, open Window → Extension Warehouse and sign in with your Trimble ID.
2. Search for the extension and open its page.
3. Click Install. SketchUp asks for confirmation, downloads and registers the extension in one step.
4. Restart SketchUp if the toolbar does not appear immediately — some extensions only build their menus on startup.

Route 2 — installing an .rbz file (the one you will actually use)

An .rbz is just a renamed zip that SketchUp knows how to unpack into its plugins folder. You never unzip it yourself — that is the single most common installation mistake.

1. Download the .rbz. If your browser renamed it to .zip, rename it back to .rbz — do not extract it.
2. In SketchUp open Extensions → Extension Manager (Window → Extension Manager in older versions).
3. Click Install Extension, pick the .rbz, confirm.
4. SketchUp copies the files and enables the extension. Restart SketchUp once — cheap insurance that every menu and toolbar registers.

Where the files actually go

Knowing the folder matters for exactly one reason: when an install goes wrong, you clean it up here — delete the extension's .rb loader file and its matching folder, restart, and install again.

Route 3 — manual copy (last resort)

If Extension Manager refuses a file (usually a permissions or path-length problem on Windows), unzip the .rbz yourself and copy its contents — one .rb file plus one folder — into the Plugins directory above, then restart. Everything the loader needs must sit at the top level of that folder; nested folders from double-zipped downloads are the classic failure.

Installed fine, not showing up? The five real causes

• Loading policy blocks unsigned extensions. Extensions → Extension Manager → gear icon: if the policy is Identified Extensions Only, unsigned tools load silently as disabled. Set Unrestricted or ask the developer for a signed build.
• The extension is installed but disabled. Extension Manager lists it with a toggle — one click fixes a surprising share of forum threads.
• macOS quarantine. A downloaded .rbz can carry the quarantine attribute; if Extension Manager errors without a reason, run xattr -d com.apple.quarantine file.rbz in Terminal and install again.
• Version mismatch. An extension built for the Ruby version in SketchUp 2023 can fail in 2026 without a clean error. Check the developer's compatibility note — SketchUp 2026 moved to Ruby 3.4 and older binaries do not survive it.
• Toolbar exists but is hidden. View → Toolbars (Windows) or right-click the toolbar area (Mac) — the extension may be loaded with its toolbar simply unchecked.

Keeping extensions alive across SketchUp upgrades

A new SketchUp version starts with an empty plugins folder — your extensions do not migrate by themselves. The clean path: install the new SketchUp, then reinstall each extension from its current .rbz so you get builds tested against the new Ruby runtime. Copying the old Plugins folder across mostly works for pure-Ruby tools and reliably breaks for anything with native components. Every SKP Tools extension is pure Ruby for exactly this reason — new SketchUp releases are supported within days.