Blender extensions: how to install add-ons, and how to fix "remote data unavailable"

This guide is about getting extensions into Blender and keeping them working: the three ways to install, repositories, updates, and the errors that stop an install. To choose which add-ons are worth having, read the guide to the best free Blender add-ons.

From add-ons to extensions in Blender 4.2

An extension is an add-on or a theme packed as a .zip file with a manifest (blender_manifest.toml) that holds its name, version, license and compatible Blender versions. Extensions are shared on online platforms and can be installed and updated from inside Blender. The official one is extensions.blender.org; the Blender 5.2 release page counts over 1,100 free add-ons and themes there.

According to the 4.2 release notes, most add-ons that used to ship with Blender moved to this platform. A few are still bundled in 5.2, such as Node Wrangler, Rigify, and the glTF and FBX importers: you only tick them in the Add-ons section. Older add-ons that were never converted still work as "legacy" add-ons, installed from disk.

Method 1: install from Get Extensions

1. Open Edit > Preferences and go to Get Extensions.
2. The first time, an Online Extensions box explains that internet access is required. Click Allow Online Access.
3. Type the name of the extension in the search field.
4. Click Install. Add-ons are enabled right after installing.

The setting you just changed lives in Preferences > System > Network > Allow Online Access. Blender stays offline until you turn it on.

Method 2: drag and drop an add-on into Blender

Every extension page on extensions.blender.org has a Get Add-on box with a Drag and Drop into Blender button. Drag that button onto an open Blender window. Blender refreshes the repository, then shows a dialog: "Do you want to install the following add-on?", with its name, repository and size, and an Enable Add-on checkbox. Confirm and it installs like method 1.

If online access is off, Blender asks for it first. If the extension does not support your Blender version or operating system, it stops with "The extension is incompatible with this system".

You can also drag a downloaded extension .zip into Blender: that is the same as installing from disk. And if you were looking for a way to drag model files into the viewport, the platform has an extension called Drag and Drop Support which, in its own words, supports and improves drag and drop imports, for formats such as FBX, OBJ, glTF and STL.

Method 3: Install from Disk

1. Download the .zip and keep it zipped.
2. In Preferences, Get Extensions or Add-ons section, click the small down arrow at the top right and choose Install from Disk.
3. Select the file. The Enable on Install option, on by default in the file browser, enables it; if you turned it off, tick its checkbox in the Add-ons list.

An extension installed this way goes into a local repository and gets no updates. Install the new .zip yourself when a new version comes out.

AutoMirror and 3D Print Toolbox in Blender 4.2 and later

Both shipped with Blender up to 4.1 and are now on extensions.blender.org, compatible with Blender 4.2 and newer. Install either one by name from Get Extensions, or by drag and drop from its page.

• Auto Mirror is listed under the Community team, offered as it is with limited support. It cuts a mesh along an axis through the object origin, deletes one half and adds a Mirror modifier, which it can also apply. Its panel sits in the sidebar (N), Edit tab.
• 3D Print Toolbox checks a mesh before printing (volume, area, bad geometry), repairs it with Make Manifold, hollows it and exports STL, PLY or OBJ. Its panels are in the sidebar, 3D Print tab, in Object Mode and Edit Mode. The guide to 3D printing with Blender uses it step by step.

If you carried your preferences over from 4.1 or earlier, the Add-ons section may show a Missing Built-in Add-ons panel that lists the ones you used and that moved, each with an Install button.

Repositories: where extensions come from

A repository is a source Blender reads extensions from. By default there is one remote repository, named extensions.blender.org, with the URL https://extensions.blender.org/api/v1/extensions/, plus two local ones. The Repositories button at the top right of Get Extensions lists them.

To use another platform, open that panel, click + > Add Remote Repository and paste the URL it gives you; some ask for an Access Token. Check for Updates on Startup makes Blender look for updates at launch. The - button removes a repository, and Remove Repository & Files also deletes its extensions, permanently.

How to fix "remote data unavailable"

Blender shows one of two messages:

• Repository: "extensions.blender.org" remote data unavailable, sync with the remote repository. Online access is on, but the listing was never downloaded.
• Repository: "extensions.blender.org" remote data unavailable, either allow "Online Access" or disable the repository to suppress this message. Online access is off.

Work through these steps in order.

1. Allow online access in Preferences > System > Network. If the line "Disabled on startup, overriding the preference" appears, Blender was launched with --offline-mode: remove that option from your shortcut or script.
2. Sync by hand. In Get Extensions, open the down arrow at the top right and click Refresh Remote. It is the first fix suggested on Blender's official bug tracker.
3. Check the repository. Under Repositories, extensions.blender.org must be there, enabled, with the URL above.
4. Update Blender. On Windows, a certificate (SSL) problem stopped some installs from reaching the platform. The fix landed in Blender 5.2.1, so on 5.2.0 install the latest 5.2 release.
5. Check your network. The official reports name firewalls and security software, VPNs, slow connections that time out, and corporate SSL filtering. The manual's network troubleshooting page says a 403 error on a network that adds its own SSL layer cannot be fixed inside Blender: an administrator has to allow extensions.blender.org.
6. Read the actual error. On Windows, open Window > Toggle System Console, run Refresh Remote again and look for CERTIFICATE_VERIFY_FAILED (certificate problem) or HTTP error (403) (connection refused).
7. Work around it. As Blender itself suggests, while offline use Install from Disk with the .zip downloaded from the website.

Update, disable and uninstall

• Update: with online access on, Blender checks the official repository at startup (Check for Updates on Startup is ticked for it by default) and shows a notice in the status bar. To check right away, run Refresh Remote. An Update button appears next to each outdated extension, and Install Available Updates in the top-right menu updates them all.
• Disable: untick the add-on in the Add-ons section. The manual recommends this over uninstalling when you only want to stop it for a while.
• Uninstall: in Get Extensions, open the arrow menu on the extension's row and choose Uninstall. For a legacy add-on, expand it in the Add-ons section and click Uninstall. Bundled add-ons are marked Built-in and can only be disabled.

Other common errors

• "The extension dropped was not found in the remote repository." Blender found the repository, but the extension does not support your Blender version or platform, or is not part of that repository. A first sync that timed out can cause it too: run Refresh Remote and drag it again.
• "Online access required to install or update." Allow Online Access, as above.
• The add-on is installed but nothing shows up. Check that it is ticked in the Add-ons section, then look in the sidebar tabs. If it refuses to enable, the manual's advice is to read the errors in the console.