What is the UNITYPACKAGE file format?
A .unitypackage file is Unity Technologies' proprietary format for packaging and distributing Unity assets between projects and through the Asset Store. Under the hood it is a gzip-compressed TAR archive - rename the file to .tar.gz and any tool such as 7-Zip can decompress it, but assets only reproduce correctly when imported through the Unity Editor.
Inside, the archive holds one directory per asset, named by the asset's 128-bit GUID. Each directory contains:
- the raw asset data bytes
- a
.metafile carrying the GUID and import settings - a
pathnametext entry recording the original project-relative path - an optional
preview.pngthumbnail
This layout lets Unity reconstruct the original folder structure and keep cross-asset references intact on import. To import, drag the file onto the Unity Editor window or use Assets > Import Package.
The .unitypackage has been the standard distribution unit for the Unity Asset Store since its 2010 launch and remains supported in Unity 6. It coexists with the newer Unity Package Manager (UPM) format, which replaces this approach with a plain tarball and a package.json manifest installed through the Package Manager window rather than imported directly.
The archive carries a gzip CRC-32 checksum but includes no cryptographic signature, so authorship cannot be verified without external tooling.
Security & safety
RISK: MEDIUMA .unitypackage can contain C# scripts (.cs), editor scripts and DLLs that run inside the Unity Editor when imported - so a malicious package can execute code in your project, not just add inert art. Import packages only from trusted sources (the official Unity Asset Store vets submissions; random forum/torrent packages do not). Review included scripts/DLLs before importing, and treat a downloaded package like any third-party code. Extracting it as .tar.gz first lets you inspect what's inside.
Format details
in a nutshellPrograms that open UNITYPACKAGE files
Windows2 apps
7-Zip
Open-source Inspect contents only: rename to .tar.gz (or open directly), extract the gzip then the tar to browse raw assets - not a substitute for importing into Unity. 
Unity Editor
Freemium Open a Unity project in Unity Hub, then Assets > Import Package > Custom Package and select the .unitypackage (or double-click it with a project open). Free Personal tier works. 
macOS2 apps
Unity Editor
Freemium Open the project in Unity Hub and use Assets > Import Package > Custom Package, or double-click the .unitypackage with a project open.
The Unarchiver / tar
Free Rename to .tar.gz to extract and inspect the raw assets; importing into Unity is still required to use them properly. 
Linux1 app
Unity Editor
Freemium Install via Unity Hub for Linux; open a project and Assets > Import Package > Custom Package to import the .unitypackage. Technical details
deep spec| Container format | gzip-compressed POSIX tar archive, equivalent to a .tar.gz file |
| Magic bytes | 0x1F 0x8B at byte offset 0 (standard gzip signature) |
| Compression | gzip / DEFLATE applied to the entire archive stream |
| Internal structure | One directory per asset, each directory named by the asset's 128-bit GUID |
| Per-asset entries | Asset data file, .meta file (GUID + import settings), pathname text file, and an optional preview.png thumbnail |
| Asset identification | Each asset is assigned a 128-bit GUID stored in its accompanying .meta file; GUIDs survive round-trips between projects |
| Path restoration | A pathname text entry inside each GUID folder records the original project-relative path, used to reconstruct the folder layout on import |
| Integrity check | gzip CRC-32 on the compressed stream; no cryptographic signature or code-signing is applied |
| Encryption | None - no built-in encryption; archive contents are fully readable after decompression |
| MIME type | application/octet-stream (primary); application/gzip also used by some hosts |
| Typical file size | Tens of kilobytes to several gigabytes, depending on the volume of textures, models and audio included |
| Platform support | Windows, macOS and Linux - wherever the Unity Editor or a tar-capable tool is available |
| Import method | Drag the file onto the Unity Editor window, or use Assets > Import Package in the menu bar |
| Relation to UPM | Distinct from Unity Package Manager packages, which use a plain tarball with a package.json manifest and are installed via the Package Manager window rather than imported as assets |
| Released | Mid-2000s (Unity asset export; Asset Store launched 2010) |
| Latest version | Legacy .unitypackage export (current Unity 6); coexists with the newer UPM/tarball package format |
| Specification | docs.unity3d.com |
UNITYPACKAGE conversions
Community Q&A
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