Which folder do I select when adding a Fusion 360 add-in from a ZIP download?

Select the folder that contains the .manifest file, never the .manifest, .py or .zip file itself. On Windows, open the .bundle folder and select the Contents folder inside it. On macOS, select the unzipped folder named after the add-in directly (macOS downloads have no .bundle or Contents folder).

How do I approve a VanThanBK Fusion add-in on macOS first launch?

If macOS shows a Not Opened security prompt when the native runtime opens for the first time, click Done to keep the installed files, open System Settings › Privacy & Security, scroll to Security, click Open Anyway or Allow Anyway for _runtime.cpython-314-darwin.so (the add-in’s runtime file), then run the add-in again in Fusion; if macOS asks again, click Open Anyway.

Why is the add-in still running the old version after updating?

In Utilities › Add-Ins › Scripts and Add-Ins, clear Run on Startup for the old add-in, click Stop, and exit Fusion completely before replacing the installed folder. Stop and Run alone without restarting Fusion can leave previously loaded Python code in memory.

Install a Fusion 360 Add-in (Windows & macOS)

Q: How do I fix "An Application Control policy has blocked this file" (_runtime.cp314-win_amd64.pyd) on Windows?

This message comes from Windows 11 Smart App Control or an IT CodeIntegrity policy blocking the native runtime file in pyencode_runtime. Open Windows Security › App & browser control › Smart App Control settings; if it is On or Evaluation and turning it off is acceptable for your computer, set it to Off, then close and restart Fusion. If it is already Off, ask your IT administrator to allow the file.

First install on Windows

Download the Windows ZIP
From the add-in's page on this website, or Info › Download latest version inside an installed add-in.
Unzip it into a folder that stays
Unzip, then move the folder ending in .bundle (for example WeldmentsPro.bundle) to Documents › Fusion Add-Ins. Fusion loads it from there every time: do not leave it in Downloads and do not delete it later.
Open Scripts and Add-Ins in Fusion
Start Fusion and go to:
UtilitiesAdd-InsScripts and Add-InsAdd-Ins tab+
4
Select the Contents folder, then Select Folder
Open the .bundle folder and select the Contents folder inside it.
Select Folder
- Fusion Add-Ins
- WeldmentsPro.bundle
- Contentsselect this
- WeldmentsPro.manifest
Pick a folder, never the .manifest, .py or .zip file itself.
Run it
Select the add-in in the list, click Run and tick Run on Startup so it loads every time. Its Info or About command shows the version.

Installed from the Autodesk App Store? Run the downloaded installer, start Fusion and continue from step 5.

Update on Windows

Save your work
If you keep your own library or preset files inside the add-in folder, copy them somewhere else first.
Stop the old version
UtilitiesAdd-InsScripts and Add-Ins
Select the add-in, untick Run on Startup and click Stop.
Quit Fusion completely
Stop and Run alone keep the old code in memory; only a full restart loads the new version.
Replace the folder
Delete the old .bundle folder and unzip the new Windows download in the same place with the same name. Fusion then finds it at the path you added before.
Start Fusion and check the version
Run the add-in if it is not running yet, tick Run on Startup and check the version in Info or About.

Unzipped somewhere else? Add the new folder with + (the Contents folder) and remove the old entry from the list. App Store install? Quit Fusion, run the new installer, then continue from step 5.

Weldments Standard and Pro: run one edition at a time. To switch, add the other edition's folder with +, untick Run on Startup for the one you leave, and restart Fusion.

Fix a problem on Windows

It is not in the list, or nothing happens when I click Run

The wrong folder was added. Remove the entry, click + again and select the Contents folder inside the .bundle.

Select Folder

Fusion Add-Ins
WeldmentsPro.bundle
Contentsselect this
WeldmentsPro.manifest

Also check that you downloaded the Windows build.

It still runs the old version after updating

In Scripts and Add-Ins, select the add-in and compare Details › Full Path with the folder you replaced. Then untick Run on Startup on any other copy, quit Fusion completely and start it again.

Windows blocked the add-in’s runtime file

An Application Control policy has blocked this file (_runtime.cp314-win_amd64.pyd)

Smart App Control (Windows 11) or an IT policy refuses to load the file. A Defender exclusion does not help.

Open Windows SecurityApp & browser controlSmart App Control settings
If it shows On or Evaluation, choose Off. On many Windows versions it cannot be turned back on without reinstalling Windows, so decide whether that is fine for your computer first.
Quit Fusion completely, start it again and Run the add-in.

Already Off? Then an IT policy blocks it: ask your administrator to allow the file. Event Viewer › Applications and Services Logs › Microsoft › Windows › CodeIntegrity › Operational names the policy.

Microsoft Defender removed a file

pyencode runtime directory contains unsigned files or directories

Quit Fusion. In Windows Security › Virus & threat protection › Protection history, open the entry for the add-in's file and choose Actions › Restore.
Or delete the unzipped folder, download the ZIP again and unzip it into a new, empty folder, then follow Update from step 4.

The message also appears when a new version was unzipped over an old copy: delete the folder first, then unzip.

Uninstall on Windows

Keep it, stop loading it

In Scripts and Add-Ins, select it, untick Run on Startup and click Stop. You can Run it again any time.

Remove it

Untick Run on Startup, click Stop and quit Fusion.
Delete that add-in's .bundle folder (copy your own files out of it first). Installed with the App Store installer? Use Settings › Apps › Installed apps.
Start Fusion and remove the entry if it is still listed.

Your Fusion designs and exported files stay. Uninstalling does not cancel a subscription; manage billing where you bought it.

First install on macOS

Download the macOS ZIP
From the add-in's page on this website, or Info › Download latest version inside an installed add-in.
Unzip it into a folder that stays
Unzip, then move the folder named after the add-in (for example WeldmentsPro) to Documents › Fusion Add-Ins. Fusion loads it from there every time: do not leave it in Downloads and do not delete it later.
Open Scripts and Add-Ins in Fusion
Start Fusion and go to:
UtilitiesAdd-InsScripts and Add-InsAdd-Ins tab+
4
Select the add-in folder itself, then Open
Select the unzipped folder. macOS downloads have no .bundle and no Contents folder.
Select Folder
- Fusion Add-Ins
- WeldmentsProselect this
- WeldmentsPro.manifest
Pick a folder, never the .manifest, .py or .zip file itself.
Run it
Select the add-in in the list, click Run and tick Run on Startup so it loads every time. Its Info or About command shows the version.
First run only: if macOS says “Not Opened”, allow it
The prompt names the add-in's runtime file, _runtime.cpython-314-darwin.so. Click Done (not Move to Trash), then open:
System SettingsPrivacy & SecuritySecurityOpen Anyway
The Open Anyway button sits next to the line about _runtime.cpython-314-darwin.so.
Run the add-in again
Back in Fusion, open Scripts and Add-Ins, select the add-in and click Run once more.
If macOS asks again, click Open Anyway. A newer version can ask once more after an update.

Installed from the Autodesk App Store? Run the downloaded installer, start Fusion and continue from step 5.

Update on macOS

Save your work
If you keep your own library or preset files inside the add-in folder, copy them somewhere else first.
Stop the old version
UtilitiesAdd-InsScripts and Add-Ins
Select the add-in, untick Run on Startup and click Stop.
Quit Fusion completely
Stop and Run alone keep the old code in memory; only a full restart loads the new version.
Replace the folder
Delete the old folder and unzip the new macOS download in the same place with the same name. Fusion then finds it at the path you added before.
Start Fusion and check the version
Run the add-in if it is not running yet, tick Run on Startup and check the version in Info or About.
First run only: if macOS says “Not Opened”, allow it
The prompt names the add-in's runtime file, _runtime.cpython-314-darwin.so. Click Done (not Move to Trash), then open:
System SettingsPrivacy & SecuritySecurityOpen Anyway
The Open Anyway button sits next to the line about _runtime.cpython-314-darwin.so.
Run the add-in again
Back in Fusion, open Scripts and Add-Ins, select the add-in and click Run once more.
If macOS asks again, click Open Anyway. A newer version can ask once more after an update.

Unzipped somewhere else? Add the new folder with + (the add-in folder itself) and remove the old entry from the list. App Store install? Quit Fusion, run the new installer, then continue from step 5.

Weldments Standard and Pro: run one edition at a time. To switch, add the other edition's folder with +, untick Run on Startup for the one you leave, and restart Fusion.

Fix a problem on macOS

It is not in the list, or nothing happens when I click Run

The wrong folder was added. Remove the entry, click + again and select the unzipped add-in folder itself.

Select Folder

Fusion Add-Ins
WeldmentsProselect this
WeldmentsPro.manifest

Also check that you downloaded the macOS build.

It still runs the old version after updating

In Scripts and Add-Ins, select the add-in and compare Details › Full Path with the folder you replaced. Then untick Run on Startup on any other copy, quit Fusion completely and start it again.

macOS will not open the add-in’s runtime

“_runtime.cpython-314-darwin.so” Not Opened · Apple could not verify it is free of malware

Click Done (not Move to Trash).
Open System SettingsPrivacy & Security scroll to Security and click Open Anyway (or Allow Anyway) next to _runtime.cpython-314-darwin.so.
Back in Fusion, open Scripts and Add-Ins, select the add-in and click Run once more.
If macOS asks again, click Open Anyway.

Uninstall on macOS

Keep it, stop loading it

In Scripts and Add-Ins, select it, untick Run on Startup and click Stop. You can Run it again any time.

Remove it

Untick Run on Startup, click Stop and quit Fusion.
Delete that add-in's folder (copy your own files out of it first). Installed with the App Store installer? Use its uninstaller.
Start Fusion and remove the entry if it is still listed.

Your Fusion designs and exported files stay. Uninstalling does not cancel a subscription; manage billing where you bought it.

Install, update or uninstall a Fusion 360 add-in

First install on Windows

Update on Windows

Fix a problem on Windows

It is not in the list, or nothing happens when I click Run

It still runs the old version after updating

Windows blocked the add-in’s runtime file

Microsoft Defender removed a file

Uninstall on Windows

Keep it, stop loading it

Remove it

First install on macOS

Update on macOS

Fix a problem on macOS

It is not in the list, or nothing happens when I click Run

It still runs the old version after updating

macOS will not open the add-in’s runtime

Uninstall on macOS

Keep it, stop loading it

Remove it

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