A Unity project’s Library folder contains generated working data; Assets contains your project content. They require very different decisions. If you are trying to free space, first identify which project the folder belongs to and whether you will need to reopen it soon.
Do not confuse the project’s Library directory with your Mac’s ~/Library directory. A command intended for one has no business being applied to the other.
Read the project root before touching it
- Assets: scenes, scripts, textures, and other source content. Keep associated metadata.
- Packages: package configuration and potentially embedded project dependencies.
- ProjectSettings: settings needed to reproduce the project.
- Library: local imported and generated working data.
Unity’s project-directory documentation explains that Library is regenerated, but warns that deleting it forces reimporting and recompilation and recommends deletion only as a last resort for serious errors. It is therefore a poor routine cleanup habit for active work.
Choose a strategy for active and inactive projects
For an active project, keep its working data if you have room. Losing an afternoon to rebuilding a cache can be a worse outcome than moving an unrelated video archive. First measure the project and identify other large folders with the Unity storage overview.
For an inactive project, consider archiving the complete project to another drive and verifying it there. If you maintain a reproducible source archive without generated data, test that archive in a separate folder before trusting it. Version control alone is not proof that every local asset was committed.
Build an archive you can actually restore
- Record the exact Unity Editor version and the target platform.
- Save and close the project. Check version-control status for uncommitted or ignored work.
- Back up source content, settings, package manifests, local packages, and any external dependencies.
- Open a test copy with the intended Editor and allow its import to complete.
- Open a representative scene and run the project or a relevant build before deleting the only working copy.
These are restoration checks, not a claim that every Unity project has the same layout. A project using a local package outside its root can appear backed up while still depending on files you did not copy.
Why the space comes back
If your next action is to reopen the same project, expect regenerated working files to consume space again. Measure storage after the import completes rather than immediately after removing a folder. A cleanup that lasts ten minutes is a sign that capacity planning may be more useful than repeated deletion.
Another common mistake is keeping several test clones open during the investigation. Each may have its own working data. Name the test copy clearly, record why it exists, and retire it once the restoration test is complete.
Check old Editor installations separately
Project data and installed Editor versions are separate storage pools. If you have retired a toolchain, follow our guide to removing old Unity Editors. Unity Hub’s installation management instructions distinguish uninstalling an Editor from merely removing its entry from Hub.
Stop when you have a verified archive or a clearly unused installation to remove. Avoid a script that blindly targets every folder called Library across your home directory.