MacSweep — Free Mac Cache Cleaner
with full taxonomy audit

Every app installed on your Mac is entitled to write temporary data into ~/Library/Caches/ — a per-user folder that Finder hides by default. Each app gets its own subdirectory, usually named after its bundle identifier (e.g. com.apple.Safari, com.spotify.client, com.adobe.Photoshop). These caches are designed to be expendable: macOS never guarantees they will survive a reboot, and apps are supposed to rebuild them on demand. In practice, apps rarely clean up after themselves, and the combined size on a Mac used for twelve months typically lands between 4 GB and 18 GB. Safari's cache database alone can reach 1–2 GB when the browsing cache limit is set to "Automatically". Spotify grows a local audio cache of 2–5 GB by default. Creative Cloud applications each maintain separate cache directories and can collectively occupy 8–12 GB. MacSweep builds a per-app breakdown of the entire ~/Library/Caches/ tree, flags caches that are safe to remove immediately (no open file handles, bundle ID maps to an installed app), and separates them from caches held by a currently running process. Clearing this layer is the first action any mac cleaner should take — and it is universally safe when done while the relevant apps are closed.

A second subdivision within this family is the derived content cache: icon services stores every scaled app icon your system has ever rendered; QuickLook maintains preview thumbnails for every document you have opened; Spotlight keeps document-content extracts that accelerate search. These are auto-regenerated on demand, so removing them costs a brief re-index but no data loss. On machines that have not been cleaned in over a year, this sub-layer alone accounts for 1–3 GB.

Browsers are the single most prolific cache writers on a typical Mac, and each browser follows its own storage architecture. Safari stores its cache inside the standard ~/Library/Caches/com.apple.Safari/ folder, so the system's standard cleanup path covers it — but the database also holds a WebKit resource timing log and a HSTS policy list that persist independently of the main cache. Chrome maintains a separate ~/Library/Application Support/Google/Chrome/Default/Cache/ directory, uses LevelDB for history, and can consume 500 MB to 2 GB depending on how many tabs you leave open across sessions. Firefox separates its profile into a Profiles/ folder under ~/Library/Application Support/Firefox/, with a distinct cache2/ subfolder that stores response bodies in a chunked file format not visible to a normal directory listing. Arc (the newer Chromium fork) inherits Chrome's cache layout but adds its own sidebar-tab persistence layer in ~/Library/Application Support/Arc/.

Beyond raw HTTP cache data, each browser accumulates: session cookies (often tracking data from sites you visited once), service-worker caches that implement offline functionality, IndexedDB stores for web apps, WebSQL legacy databases, and media source extensions caches for streaming video. Clearing all of these requires app-specific path knowledge — a generic "delete everything in Caches" sweep will miss the Chrome profile folder and the Firefox cache2 tree entirely. MacSweep ships a browser-aware module that maps each installed browser to its full cache footprint across Caches, Application Support, and the hidden Library containers, and reports how much of each category is safe to clear without losing saved passwords or autofill data (which are stored separately in the keychain).

Photos.app is the largest non-developer cache generator on most consumer Macs. The Photos library bundle contains not just your original images and videos but a complete set of derived media: thumbnail pyramids at five size tiers (used by the grid view), HEIC-to-JPEG render cache, Smart Album preview stills, face-recognition bounding-box tensors, scene-classification embeddings generated by the on-device ML model, and editing previews for every adjustment you have applied in the last 90 days. None of this is your photo data — it is all regenerable from the originals — but it can occupy 2–6 GB on a library with 30,000+ photos. When iCloud Photo Library is enabled and "Optimize Mac Storage" is on, an additional set of low-res proxy files accumulates for every image the system has not yet downloaded in full resolution.

QuickTime and AVFoundation maintain their own video proxy caches when you edit clips in iMovie or Final Cut. Each project creates a Render Files folder that can reach 5–15 GB for a single long-form project, and these folders persist even after the project is deleted from iMovie's library. The Music app maintains a similar artwork cache — every album cover rendered at multiple resolutions — that grows to 200–800 MB on large libraries. MacSweep scans each of these media subsystems, identifies render files whose parent project no longer exists, and reports the full reclaimable size before touching anything.

Below the user-facing app layer sits a set of system-owned caches that require different handling. The most significant is the dyld shared cache — a pre-linked image of every system framework, compiled at installation time and stored in /private/var/db/dyld/. This cache is what allows macOS apps to launch in under a second: instead of linking against dozens of individual frameworks at runtime, the dynamic linker maps a single pre-built image. macOS rebuilds this automatically after OS updates, and old versions (from prior OS releases) accumulate in /System/Library/dyld/ and under /private/var/folders/ as architecture-specific variants. On Apple Silicon Macs, the cache exists in both ARM64 and ARM64e variants; on Intel, in x86_64 and x86_64h (Haswell) builds. Orphaned cache variants from a prior major release can occupy 1–3 GB.

Font caches live at ~/Library/Caches/com.apple.ATS/ and are rebuilt whenever you install or remove a font. Log files accumulate in /private/var/log/ and ~/Library/Logs/ — the unified logging system introduced in macOS Sierra writes a compressed ring buffer, but crash reports, diagnostic submissions, and per-app verbose logs can still pile up to 500 MB–2 GB. Sleep images (the hibernation file at /private/var/vm/sleepimage) can match your installed RAM in size. MacSweep approaches system caches with a conservative classification: it never removes the active dyld shared cache or any file that a live process holds open, but it surfaces the full catalogue so you can make an informed decision rather than guessing which "Other" storage you can safely recover.