A blend-file can contain Python scripts, and Blender can run some of them automatically. Blender's manual says automatic execution is disabled by default, and shows a warning when a file tries to run a script. Keep that default, and treat files from outside your studio as untrusted until reviewed.
What the manual says
Blender's Scripting and Security page explains that blend-files may include scripts. When automatic execution is off and a file tries to execute a script, a dialog lets you choose Allow Execution or Ignore.
The manual names two ways a file may run scripts automatically:
- Registered text blocks, where a text data-block has its Register option enabled and loads on start.
- Animation drivers, where Python expressions drive values. These are common in advanced rigs and animations, which is why legitimate rigs sometimes need auto-run.
It also lists manual routes that run even when auto-run is off, because they need user interaction: running a script in the Text editor, and rendering with Freestyle, which uses scripts to control line styles.
How to control it
The File Browser has a Trusted Source option you can set per file. In Preferences there is a toggle called Auto Run Python Scripts. If you enable it, Trusted Source becomes enabled by default and scripts can run when files load without going through the File Browser. The manual says a typical configuration is to trust all paths except the download directory.
For command line work, such as batch rendering, the manual says Preferences still apply but can be overridden. This is the exact form it gives:
blender --background --enable-autoexec my_movie.blend --render-anim
Use that override only in render jobs that open files your studio produced.
A studio policy in five lines
- Leave Auto Run Python Scripts off on every artist workstation.
- If you must enable it, exclude the download directory and any shared inbox folder.
- Do not enable auto-exec on render farm nodes that open files from outside vendors.
- Ask contractors to deliver exports in an interchange format where possible, and keep blend-files for review in an isolated machine.
- Keep add-ons in an inventory with source and version, the way you do for engine plugins. See the post on mod and plugin safety.
Why creative studios should care
Art pipelines move files between many hands: freelancers, asset marketplaces, outsourcing partners. A rig that needs a driver to work is a normal request. An unexplained registered text block in a prop model is a reason to stop and look.
The same habit applies to other content tools. Anything that lets a file carry scripts, and anything that loads add-ons, belongs in the same review step as code dependencies.
Where Safeguard fits
Safeguard offers SBOM and dependency scanning and a free scan at https://gold.safeguard.sh/scan for declared software dependencies. Settings in your art tools sit outside that, so write them into your workstation baseline.
Quick check
Is auto-run on by default in Blender?
According to the manual, automatic execution is disabled by default.
If auto-run is off, can a script still run?
Yes, the manual lists routes that need user interaction, such as running a script in the Text editor, which work even when auto-run is off.
Sources
Last reviewed: 19 October 2026.
