How to uninstall Postbox on Mac
Before removing Postbox, save and copy your mail profiles, local-only messages and attachments to a separate backup, then open the copy. This guide covers the official Mac download; Homebrew-specific removal is separate below.
Before uninstalling, confirm server-stored mail in webmail, and make a separate backup of the complete local profile for local-only mail and settings. Copy it outside any synchronized folder and check that copy before deleting anything. The cask names two possible support folders; neither was populated by this unlaunched test, so do not treat them as caches or delete an unverified profile. Uninstalling does not delete your mail account.
The Postbox migration instructions locate POP and local mail under ~/Library/Application Support/PostboxApp/Profiles/[your.profile]/Mail. Here [your.profile] means your actual profile directory. Preserve the complete profile, not only its Mail subfolder; mail available in webmail does not replace local-only messages and settings.
Quit and remove the app
Finish current work and quit Postbox. Check Activity Monitor for its process before removing the app in Finder. In Applications, move Postbox.app to the Trash; if you keep it elsewhere, use its actual location. Keep the Trash until your backup has been checked.
Review local data
The locations below come from the test record or the live cask; their individual treatment is explained below. Open them through Finder’s Go › Go to Folder. Copy wanted contents first; leave them if you want to keep settings or cannot establish ownership. They are optional data removal, not a prerequisite for removing the app.
~/Library/Application Support/Postbox~/Library/Application Support/PostboxApp
Check the result
This read-only check searches full process command lines, not disk contents.
pgrep -ifl 'Postbox'
No output with exit status 1 means no matching command line was found. A printed entry needs inspection in Activity Monitor because names can match unrelated processes. An error is not proof of removal. Also check that the app is absent from its original Finder location; a retained data folder or independent component does not mean the app is still installed.
If you installed it with Homebrew
Use the installed cask receipt and uninstall without zap.
brew uninstall --cask postbox
The command removes the cask’s managed application artifacts without running zap. The live cask additionally names these zap targets, which can erase settings, local data or integration files; this is Homebrew’s list, not a vendor data-location claim.
~/Library/Application Support/Postbox~/Library/Application Support/PostboxApp~/Library/Caches/com.crashlytics.data/com.postbox-inc.postbox~/Library/Caches/com.postbox-inc.postbox~/Library/Caches/Postbox~/Library/Caches/PostboxApp~/Library/PDF Services/Mail PDF with Postbox~/Library/Preferences/com.postbox-inc.postbox.plist~/Library/Saved Application State/com.postbox-inc.postbox.savedState
A direct brew uninstall --cask --zap postbox runs its own zap scope without consulting Mole’s checkboxes. Mole uses zap only when the complete scope passes its gate; unchecked or shared paths, paths outside the review boundary, unknown stanzas and unsupported directives suppress it. Selected remnants still use Mole’s deletion path.
What Mole lists
The app-name ~/Library/Application Support/Postbox folder is a review row and is not selected by default; ~/Library/Application Support/PostboxApp is also a cask review target. Protect the mail profile yourself before selecting either. The test saw only the app, so it cannot prove a populated mail profile was discovered or preserved.
These defaults assume “Remove data and settings with apps” is off. Opting in also selects eligible reviewed app data; shared stores and protected data retain individual review or stay locked.
What this test covered
The September 21, 2026 record covers the following test. The official Intel app was copied from its DMG and removed without a successful launch; Rosetta was not installed. No account was signed in and only the app appeared in that removal review. Mail profiles, message export and account sync were not tested.