llms.txt
# Plumby
> Plumby is a native macOS desktop app, with an icon in the menu bar, that shows where your Mac's disk, memory, battery and heat actually go, and clears what’s filling the disk. It finds the caches, logs, crash reports, old device backups and installers your Mac and its apps made without telling you, and explains each one in a single plain sentence. It removes only what you tick, and the optional background clean stays off until you switch it on. Everything it finds is shown and explained for nothing, always; the first 5 GB you clear and the first 3 apps you fully remove are free too. Clearing and removing beyond that is $29/year, or a one-time $79 lifetime license. The app keeps working even unrenewed. No account, and nothing expires. Requires macOS 15+ (Apple silicon or Intel).
Plumby's principle is "a mirror, not a broom": it shows what it found before it acts, and acts when you press the button — or on the Quick Plunge schedule, which is off until you turn it on. Every removable item is explained in one plain sentence: what it is, what happens if it goes, how much space it gives back, and how soon it comes back. If a row can't be explained that way, it doesn't ship. Where a thing goes is set by what it is: anything that might be a file of yours rides the Trash lane, and no setting can override that. Everything else is deleted outright by default, and one control beside the Clean button switches the whole run to the Trash instead. The lane an item will take is stated on that item's own sheet before you tick it. Anything that might be a file of yours is listed first, with its box empty; big old files, iPhone backups and installers go to the Trash, where Finder's Put Back returns them, while a few of your own items are permanent either way, such as half-finished downloads and the Trash itself. The space Plumby reports is added up from what actually left, item by item, and figures shown with "about" are estimates. Purgeable space is reported and never counted in any total. Your files never leave your Mac.
The free allowance is a budget, not a trial. Nothing expires, no account is needed, and looking is never counted: finding, explaining and measuring are free at any point, licensed or not. What is counted is only what Plumby actually changes, so the limit is on space cleared (5 GB) and apps fully removed (3) — never on how much Plumby will look at, measure or explain. Spend it and nothing is taken away: Plumby keeps finding, naming and measuring, what was already cleared stays cleared, and a license turns the clearing and removing back on.
## Key pages
- [Plumby home](https://plumby.app): what it does, features, and download
- [Pricing](https://plumby.app/pricing.md): plans and pricing, machine-readable
- [All guides](https://plumby.app/guides): the full guide library
## Storage & System Data
- [Is 256 GB enough for a MacBook Air? What actually fills it](https://plumby.app/guides/is-256gb-enough-macbook-air): Is 256 GB enough for a MacBook Air? For most people yes, but not by the margin the number suggests: macOS takes its cut before you save a single file. Here's what really fills the disk, and how to decide before you pay for 512.
- [How to clear System Data on Mac (safely, step by step)](https://plumby.app/guides/how-to-clear-system-data-on-mac): There's no button that clears System Data, because it isn't a folder. Here's how to find out what's actually in it, and the order that shrinks it, safest first.
- [How to clear cache on a MacBook Air (browser, apps, and system)](https://plumby.app/guides/how-to-clear-cache-on-macbook-air): Three different things get called cache on a MacBook Air, and most people asking this want the browser one. Here is how to clear each of them in Safari, Chrome and macOS, plus the part cleaner apps skip: clearing cache almost never makes a Mac faster.
- [What is taking up space on your Mac? The complete map](https://plumby.app/guides/what-is-taking-up-space-on-mac): Your Mac's storage bar is full but you can't find why? Here's the complete map of where Mac storage actually goes (System Data, caches, snapshots, and the apps that quietly hoard gigabytes) and where to look for each.
- [Photos eating your Mac's storage? iCloud “Optimize” explained](https://plumby.app/guides/photos-taking-up-space-mac): Photos taking up space on your Mac? Here's what the Photos library holds, what iCloud's Optimize Mac Storage really does, and how to free space safely.
- [“Not enough space to install the update” on Mac? Here's the fix](https://plumby.app/guides/not-enough-space-to-update-macos): 'Not enough space to update macOS' with several GB free? A macOS installer needs far more room than the download. Here's how much you need and how to free it.
- [Why Apple Mail is taking up so much space on your Mac](https://plumby.app/guides/mail-taking-up-space-mac): Apple Mail taking up space on your Mac? It keeps a local copy of every message and every attachment. Here's where it stores them and how to shrink it safely.
- [GarageBand's sound library is eating GBs: is it safe to delete?](https://plumby.app/guides/garageband-sound-library-storage-mac): GarageBand's sound library can use tens of GB of storage on your Mac. It's safe to delete if you don't make music; it re-downloads free anytime. One caveat first.
- [Why “Documents” takes up so much space on your Mac](https://plumby.app/guides/documents-storage-mac-explained): Documents taking up space on your Mac? That storage slice is broader than your Documents folder: it counts big files across your whole home folder. Here's how to shrink it.
- [What is “System Data” on Mac?](https://plumby.app/guides/what-is-system-data-on-mac): System Data is the catch-all bucket in Storage settings: a rough estimate, not a folder you can open. Here's what macOS counts in it, and where to find it.
- [What is “Other” storage on Mac?](https://plumby.app/guides/what-is-other-storage-mac): “Other” storage on Mac was the old name for what Apple now calls System Data: the same catch-all of caches, logs, snapshots, and backups. Here's what changed.
- [Time Machine local snapshots: the hidden GB behind “System Data”](https://plumby.app/guides/time-machine-local-snapshots-mac): Time Machine local snapshots sit on your Mac's internal disk even without a backup drive, quietly padding System Data. Here's how to see and clear them safely.
- [“Your startup disk is almost full”: what to actually do](https://plumby.app/guides/startup-disk-almost-full-mac): The 'startup disk almost full' warning on your Mac isn't just a nag; APFS needs real free headroom. Here's what triggers it and how to clear room safely.
- [What is purgeable space on Mac?](https://plumby.app/guides/purgeable-space-mac): Purgeable space on Mac is storage macOS frees up automatically when it needs room: caches, Spotlight indexes, and local snapshots you can't delete yourself.
- [Why your Mac has two “Macintosh HD” volumes](https://plumby.app/guides/macintosh-hd-data-volume-explained): Since macOS Catalina your Mac splits the startup disk into two: a sealed read-only Macintosh HD and a writable Macintosh HD - Data volume. Here's why.
- [Why is my Mac storage full when I deleted everything?](https://plumby.app/guides/mac-storage-full-explained): Why is my Mac storage full when you deleted everything? Because APFS snapshots retain old blocks, space stays purgeable, and 'System Data' won't budge.
- [How to free up space on your Mac (the honest way)](https://plumby.app/guides/how-to-free-up-space-on-mac): How to free up space on Mac without cleaner-app hype: start with Apple's own Storage tools, then the manual wins that actually pay off, ranked by safety.
- [The hidden storage on your Mac: where your disk space really goes](https://plumby.app/guides/hidden-storage-on-mac): Your Mac is quietly holding onto 100–200 GB you never chose to keep: cache, “System Data,” APFS snapshots, and files apps leave behind when you delete them. Here's what all of it actually is, and how to see it.
- [You deleted files but free space didn't change: here's the fix](https://plumby.app/guides/deleting-files-not-freeing-space-mac): Deleting files but not freeing space on Mac? Causes are an un-emptied Trash, APFS snapshots, purgeable space, or a stale Finder count, plus the fix for each.
## What’s safe to delete
- [How to delete apps on Mac that won't delete](https://plumby.app/guides/apps-wont-delete-mac): You dragged it to the Trash and macOS refused, or it came back on its own. Here is every reason a Mac app won't delete, in the order it usually turns out to be, with the fix for each one and an honest answer for the case you can't fix yourself.
- [What can you safely delete on a Mac?](https://plumby.app/guides/what-can-you-safely-delete-on-mac): Wondering what you can delete on a Mac? An honest, tiered guide: what's safe (caches, Trash, backups), what to back up first, and what you should never touch.
- [Is it safe to delete iOS backups on your Mac?](https://plumby.app/guides/is-it-safe-to-delete-ios-backups-mac): Yes, old iOS backups on your Mac are safe to delete and can free tens of GB. Here's which ones to remove, the caveats, and the safe way to do it in Finder.
- [Is it safe to delete cache files on Mac?](https://plumby.app/guides/is-it-safe-to-delete-cache-on-mac): Is it safe to delete cache on Mac? Mostly yes for user caches in ~/Library/Caches; macOS and apps rebuild them next launch. Which to clear, which to leave.
- [How to completely uninstall a Mac app (and clear the leftovers)](https://plumby.app/guides/how-to-uninstall-apps-on-mac-completely): Dragging an app to the Trash removes only the .app bundle; everything it wrote to ~/Library stays. The five kinds of Mac app, and how to fully remove each one.
- [How to clear app caches on Mac (Slack, Discord, VS Code & more)](https://plumby.app/guides/clear-app-caches-mac): Slack, Discord, VS Code and Spotify can hoard multi-GB caches. How to clear app caches on Mac safely: quit the app, empty only its Cache folder, skip real data.
- [Is it safe to delete node_modules? (and how to get the space back)](https://plumby.app/guides/is-it-safe-to-delete-node-modules): Yes, deleting node_modules is safe: it's fully reproducible from package.json and your lockfile. Here's when to delete it, how to find every stale copy on your Mac, and how to reclaim the space.
## Mac cleaners (honest takes)
- [XProtect on Mac: the antivirus your Mac already runs](https://plumby.app/guides/xprotect-mac): Your Mac has been scanning itself for malware since the day you switched it on. What XProtect, XProtect Remediator, Gatekeeper and notarization actually do, how to check the version you have, and the honest answer on whether you need antivirus as well.
- [CCleaner for Mac: what it does, and the honest alternative](https://plumby.app/guides/ccleaner-for-mac-alternative): CCleaner for Mac still exists, and it isn't malware. But macOS has no registry to clean, so the Windows habit doesn't transfer. Here's what it actually does on a Mac, the history worth knowing, and what to use instead.
- [Plumby vs CleanMyMac: an honest, side-by-side comparison](https://plumby.app/guides/plumby-vs-cleanmymac): Plumby vs CleanMyMac, compared fairly. Both clean a Mac, but they differ on measured vs estimated results, one-click vs review-first, and what you pay for. Here's which fits you.
- [An honest MacKeeper alternative (no scare tactics, no lock-in)](https://plumby.app/guides/mackeeper-alternative): Looking for a MacKeeper alternative? The current app is legitimate, but if you want Mac cleanup without the subscription, the upsell, or the reputation, here are honest picks, including what MacKeeper does that they don't.
- [The best Mac cleaner in 2026 (an honest buyer's guide)](https://plumby.app/guides/best-mac-cleaner): The best Mac cleaner is often no cleaner at all. macOS handles most housekeeping itself. Here's an honest map: when you actually need one, the trustworthy paid and free options, and what to just do yourself.
- [Is CleanMyMac safe? An honest look](https://plumby.app/guides/is-cleanmymac-safe): Is CleanMyMac safe? Yes. It's Apple-notarized, Developer-ID signed, and made by MacPaw. The real question isn't safety; it's whether you need it at all.
- [Do you actually need a Mac cleaner?](https://plumby.app/guides/do-you-need-a-mac-cleaner): Do I need a Mac cleaner? Usually not. macOS clears its own caches, logs and snapshots and offers Optimize Storage. Here's the honest exception it won't.
- [An honest CleanMyMac alternative (that shows its work)](https://plumby.app/guides/cleanmymac-alternative): A CleanMyMac alternative that shows its work: CleanMyMac is legit, but if you want measured results, a pay-once option and no auto-delete, here are honest picks.
- [The best Mac cleaner for developers](https://plumby.app/guides/best-mac-cleaner-for-developers): The best Mac cleaner for developers finds what generic cleaners miss (node_modules, Xcode DerivedData, Docker.raw), shows exact paths, never touches source.
- [The best disk space analyzer for Mac (honest picks)](https://plumby.app/guides/best-disk-space-analyzer-mac): The best disk space analyzer for Mac shows where your space went so you decide. Honest picks: DaisyDisk, GrandPerspective, OmniDiskSweeper, ncdu, and more.
- [Are Mac cleaner apps safe, or a scam?](https://plumby.app/guides/are-mac-cleaners-safe): Are Mac cleaners safe? Most reputable, notarized ones are. The scam reputation comes from old MacKeeper and fake counterfeits. Here's how to tell them apart.
## Performance & battery
- [Mac high CPU usage: which process is it, and is it a virus?](https://plumby.app/guides/mac-high-cpu-usage): A process pinned at the top of Activity Monitor is almost never malware. Here's how to read the name, how to rule out a virus in one command, and what each of the usual macOS background processes is actually doing.
- [Unified memory vs RAM: what Apple changed, and what it didn't](https://plumby.app/guides/unified-memory-vs-ram): Unified memory changes how a Mac's memory is wired, not how much a gigabyte holds. Here's what Apple changed on Apple silicon, where the claim that 8 GB behaves like 16 GB came from, and how to decide how much to buy on a Mac you can't upgrade later.
- [A Macs Fan Control alternative, and when you don't need one](https://plumby.app/guides/macs-fan-control-alternative): Macs Fan Control is free and it changes what your fans do. Plumby mostly shows the heat and which apps are working your processor, with three fan settings instead of curves. Here's the honest split, including which one you actually want.
- [MacBook battery health and cycle count: where to look, and what the numbers mean](https://plumby.app/guides/macbook-battery-health-cycle-count): macOS keeps battery health and cycle count on two different screens, and tells you neither what your model was rated for nor when the wear actually matters. Here is where both numbers live, what they mean, and how to decide between a new battery and a new Mac.
- [How to force quit on Mac, from the shortcut to the last resort](https://plumby.app/guides/how-to-force-quit-on-mac): Press Option-Command-Esc. That's the Mac's Ctrl+Alt+Delete, and it opens the Force Quit window. Here's every way to close a frozen app, in ascending order of force, and what to do when force quitting itself stops working.
- [Activity Monitor on Mac: how to read every number](https://plumby.app/guides/activity-monitor-mac): Activity Monitor is the free system monitor built into macOS. How to open it, and how to read the five tabs, including the numbers that look scary and aren't.
- [Why is my Mac slow? A complete, honest diagnosis](https://plumby.app/guides/why-is-my-mac-slow): A slow Mac is almost always one of four things: memory pressure, a runaway process, too many login items, or background work after an update. Here's how to tell which, and fix the real cause.
- [How to see which app is using your network on a Mac](https://plumby.app/guides/see-what-app-is-using-network-mac): Find out what's using your Mac's network: Activity Monitor's Network tab for per-app data, nettop and lsof for live connections and hosts, and how to see which app is quietly phoning home.
- [How to monitor CPU temperature on a Mac](https://plumby.app/guides/monitor-cpu-temperature-mac): macOS has no built-in CPU temperature readout, and the powermetrics command every guide gives you no longer works on Apple silicon. What does work, what's normal, and why the hot process matters more than the number.
- [The best Mac menu-bar system monitor (honest picks for 2026)](https://plumby.app/guides/mac-menu-bar-system-monitor): The best Mac menu-bar system monitor depends on what you want: pure sensor detail (iStat Menus, Stats), a monitor-plus-cleaner suite (Sensei), or an app that explains each reading in plain words (Plumby). Honest picks, with prices.
- [An iStat Menus alternative that also acts on what it shows](https://plumby.app/guides/istat-menus-alternative): Looking for an iStat Menus alternative? For pure sensor readings, iStat Menus ($11.99) and Stats (free) are hard to beat. If you want a monitor that can also quit the app or clear the disk, here's the honest difference.
- [Mac slow to start up? Trim login items & launch agents](https://plumby.app/guides/mac-slow-startup-login-items): A slow Mac startup usually means too many login items and leftover launch agents loading at boot. Here's how to trim them safely, starting in System Settings.
- [Mac slow after a macOS update? Why it happens (and what helps)](https://plumby.app/guides/mac-slow-after-update): Mac slow after a macOS update? It's usually temporary background work (Spotlight reindexing, Photos re-analyzing, iCloud re-syncing), not a broken Mac.
- [Is 8 GB RAM enough on an M-series Mac? Swap & unified memory](https://plumby.app/guides/is-8gb-ram-enough-mac): Is 8 GB RAM enough on a Mac? On Apple silicon, unified memory and fast SSD swap make it fine for light-to-moderate use; here's when to buy 16 GB+.
- [Android Studio eating 50–100 GB on your Mac? Here's what to clear](https://plumby.app/guides/android-studio-disk-space-mac): Android Studio disk space on your Mac balloons fast: Gradle caches, AVD emulators, and SDK images quietly reach 50–100 GB. Here's exactly what's safe to clear.
- [Why Xcode takes up 50+ GB on your Mac (and what's safe to delete)](https://plumby.app/guides/xcode-taking-up-space-mac): Xcode taking up space on your Mac? DerivedData, DeviceSupport, and simulators quietly reach 20–50 GB. Here's exactly where it goes and what's safe to delete.
- [What's draining your Mac's battery?](https://plumby.app/guides/whats-draining-my-mac-battery): Wondering what's draining your Mac battery? Find it with the battery menu's Significant Energy list, Activity Monitor's Energy tab, and pmset; no app needed.
- [Mac memory pressure explained (green, yellow, red)](https://plumby.app/guides/mac-memory-pressure-explained): Mac memory pressure, not free RAM, is the real signal. Here's what green, yellow, and red mean in Activity Monitor, and why RAM cleaner apps don't help.
- [MacBook fans loud and running hot? Here's what's actually causing it](https://plumby.app/guides/mac-fans-loud-running-hot): MacBook fans loud and running hot? Fans spinning up under load is normal; the fix is finding which process is working the CPU or GPU. Here's how to check.
- [Why Chrome (and “Google Chrome Helper”) eats your Mac's memory](https://plumby.app/guides/chrome-using-too-much-memory-mac): Chrome using too much memory on Mac is mostly its multi-process design: each tab and extension is a separate process. Here's how to find and fix the real hog.
- [How to find and kill the process using port 3000 on macOS](https://plumby.app/guides/kill-process-on-port-3000-mac): Port 3000 already in use? Find the exact process holding it with lsof, stop it properly, and handle the cases the one-liner misses:
