An AEP file is used by After Effects to store project structure instead of being a final video, holding compositions, layer stacks, animation items like timing keys and expressions, effects with adjustable settings, masks, mattes, and 3D objects like cameras or lights, and it typically stores only links to the actual footage so the file itself stays lean regardless of how large the external media is.

Because AEP projects depend on external file paths, moving or renaming sources—or copying only the AEP to another system—can trigger “clip not found” errors, making the Collect Files workflow (or a manual folder gather) the usual method to keep everything linked, and if an AEP doesn’t open correctly, factors like where it came from, what files accompany it, what Windows says under “Opens with,” or a brief text-editor inspection can help identify whether it’s an authentic AE project or a separate vendor’s format.

When an AEP appears to fail to load assets on another computer, it’s usually because it works as a blueprint that references outside files rather than storing them internally, meaning After Effects relies on absolute paths to footage, images, audio, and proxies, and once the project moves to a system with different drive letters, folder structures, or missing media, AE can open the project but not the assets, resulting in Missing/Offline Media until everything is relinked.

Projects can seem “broken” even with all footage available when the new PC doesn’t have the right fonts, causing text to shift unexpectedly, or lacks third-party plugins so effects appear missing, or when an older version of After Effects can’t read newer project elements, and the stable solution is to use Collect Files or duplicate the exact folder structure and then relink, after which matching fonts, plugins, and paths typically restore the project instantly.

An AEP file is essentially a small structural database that captures your entire After Effects project without containing the heavy media, storing comp properties like resolution, frame rate, duration, nesting, and background color, every timeline layer and its transforms such as position, scale, rotation, opacity, blending, mattes, parenting, timing, plus all animation instructions like keyframes, easing curves, motion blur, markers, and expressions, along with complete effect configurations and any mask or roto data including shape outlines, feather, expansion, and animated vertices.

Using 3D in AE means the AEP saves your cameras, lights, 3D-layer attributes, and render settings, plus project-structure info like bins, label coloring, interpretation settings, and proxy references, but not the source media itself—videos, stills, and audio live outside the project—so the AEP acts as the blueprint and the file paths for your assets, which is why moving or renaming them leads to missing-media notices until you relink If you have any type of concerns pertaining to where and ways to utilize AEP file support, you can call us at our web site. .