Leftover files after uninstalling an app on a Mac

The six places an app leaves things

Press Shift-Command-G in Finder and paste any of these. The ~ is your home folder; the ones without it are shared by every user on the Mac and need an administrator password to change. For what else is in your Library and what is safe there, see the Library folder on a Mac.

• ~/Library/Application Support/ — the app's data: settings, databases, licences, downloads. A folder here is often named after the developer rather than the app, and for many apps it is the data itself, not a copy.
• ~/Library/Caches/ — named by bundle ID (com.developer.app). Regenerable while the app existed; dead weight once it is gone.
• ~/Library/Preferences/ — the app's settings, in a .plist file named by bundle ID. Small, and safe.
• ~/Library/Containers/ — where a sandboxed app, which is every Mac App Store app, keeps everything. Inside its container is a whole Data/Library of its own, with its own Application Support, Caches and Preferences.
• ~/Library/Group Containers/ — folders shared between an app and its helpers or extensions, named by a team identifier. WhatsApp's chats and media live here, for example.
• ~/Library/LaunchAgents/, /Library/LaunchAgents/, /Library/LaunchDaemons/ — a .plist that tells macOS to start a helper at login or at boot. A helper whose app is gone may still be running, which is why an uninstalled app can keep appearing in Login Items.

Smaller ones worth a glance: ~/Library/Saved Application State/ (window positions), ~/Library/Logs/, ~/Library/HTTPStorages/ and ~/Library/WebKit/, each with a folder per bundle ID; and /Library/PrivilegedHelperTools/ and /Library/Application Support/ for apps that asked for an administrator password when they installed.

How to find them

Most leftovers are named after the app's bundle ID, which is why searching for the app's name misses them. If the app is still installed, get the ID first:

mdls -name kMDItemCFBundleIdentifier /Applications/AppName.app

If it is already gone, the ID is usually the developer's reversed domain plus the app, and a search by either part finds it:

# anything in your Library carrying the name, three folders deep
find ~/Library -maxdepth 3 -iname "*appname*" 2>/dev/null

# the shared folders, which need admin rights to change
find /Library -maxdepth 3 -iname "*appname*" 2>/dev/null

# helpers still registered to start at login
launchctl list | grep -i appname

Two more tells. In Finder, sort ~/Library/Containers and ~/Library/Application Support by Date Modified: a folder nothing has written to since the day the app went is a leftover. And System Settings → General → Login Items & Extensions → Allow in the Background lists helpers by the name of the app that installed them, so an entry for an app you no longer have is a LaunchAgent to find.

What is safe to remove

• Caches, Saved Application State, Logs, HTTPStorages, WebKit: yes. For an app that is gone, nothing reads them and nothing will.
• Preferences: yes. If you reinstall the app, it starts with default settings, which is the whole cost.
• LaunchAgents and LaunchDaemons of an app that is gone: yes, but unload first. Move the .plist to the Trash, then either restart or run launchctl bootout gui/$(id -u) ~/Library/LaunchAgents/the.file.plist so the helper stops now rather than at the next login. Anything in /Library needs sudo.
• Containers, Group Containers and Application Support: look first. This is the app's data. For a notes app, a password manager or anything with a library, it may be the only copy of your work, and the folder name rarely says so. Open it, see what is there, export anything you want, and only then move it to the Trash.

Move things to the Trash rather than deleting them outright, and leave the Trash alone for a week. Reinstall the app before you empty it and it finds its data again. And leave three kinds of folder where they are: anything starting com.apple., which is macOS's own; a vendor folder (Google, Adobe, Microsoft) that an app you still use shares; and anything you cannot identify. Chrome is the common case of a vendor folder: how to uninstall Google Chrome says which of Google's folders to remove and which to keep.

Why it comes back

A leftover from a gone app does not grow; it sits at the size it was. What grows is the next app's, and the one after that, because every app you try leaves this set behind when it goes. A folder in Containers that is still getting bigger belongs to something that is still running, which is the reason to find the LaunchAgent before you find the data.

Where the app comes in

RefreshYourMac has a category for exactly this: Data Left by Removed Apps, rated Review before deleting. It lists a folder from ~/Library/Containers or ~/Library/Group Containers only when the app that owned it, and every helper or extension that used it, is no longer installed; only once nothing has written to it on the last eight days you used this Mac; and only if nothing has it open. macOS's own folders are never listed. Clean moves what you choose to the Trash after a confirmation, and if you reinstall the app before emptying the Trash you can put it back. A scheduled clean never touches it.

Around it sit the broader categories: App Containers, rated Backup recommended, which has no bulk clean and lets you pick a container one at a time or move it to another drive; Group Containers, rated Review before deleting; and Application Support, which is Protected: measured and shown for its size, never deleted, because no scan can tell a cache from the only copy of somebody's work. Data Left by Removed Apps does not look in Application Support, Preferences or LaunchAgents, so those stay a hand job, with the steps above. All of these are in the download edition, not the Mac App Store edition.

For an app that is still installed, the better order is to let the app remove its own leftovers on the way out: how to uninstall apps on a Mac covers RefreshYourMac's Uninstall an App, which finds every piece by bundle ID before the app is gone, and macOS uninstaller apps says what to check in any uninstaller before you trust it with your Library. For Docker, whose own uninstaller leaves two folders to remove by hand, see how to uninstall Docker on a Mac.