A disk can be nearly full without making the next step obvious. A large folder might be a project you still need, a dependency that can be downloaded again, or build output you can recreate. Sorting those apart by size alone is risky, especially when several worktrees share a codebase.
Nijia is a macOS storage analysis and cleanup app aimed at making that distinction clearer. Its central idea is to connect disk usage with developer workspaces, then let you review proposed cleanup before anything moves to the Trash. It is less a one-button disk cleaner than a tool for investigating what occupies space and deciding what to do about it.
Start with a map, not a delete button
Nijia’s Space Analysis presents disk and folder usage as a tree that you can expand to inspect what sits inside larger locations. The point is to move from a general sense that storage is disappearing to a view of which folders account for it. That can be useful when project directories, system locations and other large folders compete for attention.
The app also offers cleanup suggestions, but size is not supposed to be the whole argument for removing something. Nijia’s workspace inspection is intended to add context: what a file is associated with, which workspace it belongs to, and whether it may be generated again. The landing page describes scans as local and read-only until you choose an action. That is a useful distinction for anyone who wants an inventory before granting a cleanup tool permission to change files.
There is a setup choice here. Workspace inspection starts with folders you authorize, so Nijia does not simply claim to understand every project on the Mac without your input. That boundary is sensible, but it means the view depends on selecting the relevant workspaces first.
Why worktrees change the cleanup question
For developers, a repository may occupy more space than its checked-out source suggests. Dependencies, build output and multiple linked Git worktrees can add substantial storage, while a directory’s name or size does not tell you whether it is safe to remove. Deleting an active worktree or useful build result can cost time even if some of the data is reproducible.
Nijia’s particular focus is bringing worktree and rebuildability context into this decision. It says it can show linked worktrees alongside workspace information and match derived artifacts to the worktree that can rebuild them. That gives a developer a basis for distinguishing source work from output that might be regenerated. The app also describes showing Git and agent-session evidence, though the page does not explain the underlying detection in detail.
This is the part that makes Nijia more specifically a developer workspace tool than a general disk map. If your storage problem is mostly old downloads or media, the workspace context may matter less. If you keep parallel branches, experiments or generated output around, knowing what a candidate belongs to could make a cleanup review more informed.
Review is part of the workflow
The sequence Nijia describes is deliberate: choose a workspace, inspect what is using space, consider why an item exists and what rebuilding it could involve, then select the items to move. You confirm the action before files go to the Trash. They are not immediately erased, and moving them there does not necessarily free disk space until the Trash is emptied. That extra step is a safeguard, but it also means cleanup is not automatic or complete with a single scan.
The same review principle applies to its file-organization proposals. Nijia says proposals can be edited before confirmation, and that its AI Desk Tidy feature runs locally without requiring an external AI account or API key. These are secondary tools around the storage problem, not a substitute for deciding which files should remain. System Watch adds disk, memory and load information, but the main value proposition remains inspection before removal.
Nijia is a paid app, with a seven-day free trial advertised on its site. It runs on macOS; the landing page says it supports Apple silicon and Intel Macs running macOS 13 or later. It is therefore not a cross-platform workspace cleaner, and its strongest case depends on the developer-specific context rather than broad file management alone. Nijia is worth considering for Mac developers who want to examine worktrees and rebuildable output before reclaiming disk space. It is a poor fit for someone seeking automatic deletion, a Windows or Linux utility, or a cleanup tool that requires no review.
Mac storage clarity with cleanup you review.