How to Edit a Plist File on macOS with Xcode

You can edit a property list (.plist) file on macOS in Xcode’s structured editor. Back up the file, open it in Xcode, change only documented keys and values, then save. Avoid editing a third-party app’s installed bundle: changing a signed app can invalidate its signature or break updates. For your own app, edit the project source or build settings and rebuild.

When to edit a plist directly

Property lists hold structured data—strings, numbers, Boolean values, arrays, and dictionaries. An app’s Info.plist describes its bundle; separate plists may store preferences. Use the file and key documented by the app: inventing a key will not add support for a setting.

Before editing, identify whether the file contains app metadata or a user preference. If you want to change a feature in an app you use, start in that app’s settings or documentation. A preference file may be rewritten when the app launches or quits; an installed bundle’s Info.plist is not a general settings panel.

For an Xcode project you maintain, check the target’s Info pane and build settings first. Xcode may generate Info.plist at build time, so editing a built copy can be temporary. Apple’s editing guide covers the structured editor; its build settings reference explains generated values.

Edit a plist file with Xcode

1. Install Xcode

Get Xcode from the Mac App Store. It is currently listed as free; check the listing for requirements for the version available to your Mac. Launch Xcode once after installation.

2. Make a working backup

Find the plist in Finder and duplicate it or copy it to a working folder before editing. Keep the original until you verify the change. Store backups outside an app’s .app bundle; adding files there can alter its signed contents.

3. Find the file inside an app, if needed

To inspect an app bundle, Control-click the app in Finder and choose Show Package Contents. This reveals its internal folders. Use this to locate a file, or edit only an app you maintain and can rebuild or re-sign; don’t patch a third-party app in place.

4. Open the plist in the bundle

Open Contents, then look for Info.plist. Other plists may be elsewhere, so follow the app or project documentation. For a standalone file, use its normal Finder location.

5. Open the file in Xcode

Control-click the plist and choose Open With > Xcode. If Xcode is missing, choose Other and select it from Applications. You can also open Xcode and use File > Open. A structured plist appears as key, type, and value rows.

6. Change an existing value or add a row

Click an existing value to edit it. To add a setting, Control-click in the editor and choose Add Row, or click the add control. Use the exact key documented by the app; misspelled or unsupported keys may be ignored.

7. Check the value type and save

Match the value type to the documented format: a Boolean, number, and string are not interchangeable. Arrays hold ordered items; dictionaries hold named values. Avoid guessed or duplicate keys, then press Command-S.

• String: text, such as an identifier or label.
• Boolean: true or false.
• Number: an integer or real number.
• Array or dictionary: a list or a group of named values.

8. Reopen and verify the saved file

Close and reopen the plist to confirm the value persisted. For your own project, rebuild and test a copy. If the app ignores it, check that you edited the right source file; apps can read preferences elsewhere or replace them at launch. Restore the backup or reinstall if the app fails.

Important signing and troubleshooting notes

Apple notes that modifying a signed app bundle can invalidate its signature; updates may also replace edits. For software you maintain, change the source plist or target setting, then rebuild. For ordinary preferences, use the app’s settings. Do not disable macOS protections to edit a plist.

If Xcode cannot save, work from a writable copy. If a change disappears after rebuilding, update the source or build setting. If a key is ignored, verify its spelling, type, and location in the app’s documentation.

For more detail, see Apple’s Information Property List documentation and its Technical Note on macOS code signing.