When the Unity Package Manager downloads package contents and metadata from a registry, it stores them in a global cache. This makes reusing and sharing packages more efficient, and allows you to install and update stored packages even when offline.
Note: The global cache doesn’t include packages in the .unitypackage format that come from the Asset Store. The Package Manager stores these types of packages in a separate cache. For more information, refer to Asset Store packages.
默认情况下，Unity 将全局缓存存储在根目录中，根目录取决于操作系统（在 Windows 上还取决于用户帐户类型）：
| 操作系统 | 默认根目录 | 示例 |
|---|---|---|
| Windows（用户帐户） | %LOCALAPPDATA%\Unity\cache\upm |
C:\Users\yourname\AppData\Local\Unity\cache\upm |
| Windows（系统用户帐户） | %ALLUSERSPROFILE%\Unity\cache\upm |
C:\ProgramData\Unity\cache\upm |
| macOS | $HOME/Library/Caches/Unity/upm |
/Users/yourname/Library/Caches/Unity/upm |
| Linux | $HOME/.cache/Unity/upm |
/home/yourname/.cache/Unity/upm |
Tip: You can override the location of this root directory. Refer to Customize the global cache for more information.
The Package Manager global cache uses subsidiary caches, each serving a different purpose. The Package Manager stores these subsidiary caches in subfolders under the folder of the global cache:
| 子文件夹 | 描述 |
|---|---|
db |
Registry data cache used for storing package content and metadata. |
packages |
Contains the uncompressed contents of package tarballs fetched from a registry. |
git-lfs |
Contains downloaded Git Large File Storage (LFS) files, if you’ve enabled Git LFS. |
Inside each of these subfolders, each registry has its own path so that packages hosted on different registries aren’t mixed up.
Tip: You can override the location of these folders. Refer to Customize the global cache for more information.
Starting with version 2023.2.0f1 of the Unity Editor, the size of the registry data cache (the db subfolder) is limited to 10 gigabytes (GB). When that limit is reached, the Package Manager prunes the registry data cache by evicting the least recently used content (based on oldest date a package was installed into a project). In other words, the first packages the Package Manager evicts are the ones you added to a project the longest time ago. However, although the Package Manager evicts these packages from the cache, they remain in any projects where you installed them. The next time you add these packages to a different project, the Package Manager will fetch them from the appropriate registry, rather than from your cache.
You can override the size of the registry data cache limit. For information, refer to Customize the global cache.
The user account running the Unity Editor process must have full write permissions on the root directory and its contents. Without these permissions, the Package Manager can’t download and save the package metadata and contents in the cache.