How to Fix a Mac Application That's Not Starting

Fixing file permissions or deleting preferences may help

When you launch a Mac application that you use regularly and it won't start up, or its icon bounces up and down in the Mac Dock and never finishes launching, you're bound to be frustrated. If you are lucky, this is a one-time event. You can force quit the app and try again, hopefully with success. If the application still doesn't start, there are several fixes you can use to solve why the app isn't running on the Mac.

The information in this article applies to Macs with macOS Catalina (10.15) through OS X Lion (10.10), except as indicated.

Disk Utility in macOS Mojave

Reasons a Mac Application Won't Start

If you've been running the app that won't start for a while successfully, and now it won't start, something changed. There's a chance a file became corrupt because of a system crash, or the app may need to be updated. It may be in conflict with another app, or its permissions or preferences file may have been damaged.

How to Fix an Application Not Opening on Mac

Whatever the reason, there are several possible fixes for this problem, ranging from incredibly simple to more complex.

  1. Restart the Mac. It's always smart to start with the simplest fix possible.

  2. Update the app. Check that you have the most current version of the app, and if not, update it. This is particularly important following an update to the Mac operating system. In many cases, updating the affected app cures the problem.

  3. Delete the app preference file. Plist files can become corrupt when a Mac shuts down or restarts unexpectedly or when an app freezes or crashes. As a result, the app may not open. When you delete a bad preference file, the Mac creates a new plist file that contains all the app's defaults automatically. You have to reconfigure the app's preferences afterward.

    Go to Library > Preferences and delete the plist file that matches the app. Look for the plist in this format: com.developer_name.app_name.plist.

    Apple hides the Library folder by default so that you can't accidentally make changes to it. You need to know how to display hidden files in OS X if you don't see the Library folder on your Mac.

  4. Start Mac in Safe Mode. This troubleshooting startup environment restricts most startup items and limits the operating system to use only the basic OS core. If you can start the Mac in Safe Mode and then use the app in question without problems, the likely cause is not permissions or preference files but a conflict with another app or a startup item.

  5. Repair app permissions. In OS X Yosemite and earlier, one of the first things to do when encountering an app that won't launch is to repair permissions to make sure the application and any associated files it needs have the correct permissions required to run. File permissions can get wacky once in a while. Repairing permissions is an excellent general-purpose troubleshooting step. You don't need to know what the permissions should be; the Mac keeps a database of the default permissions for most applications that you install.

    With the release of OS X El Capitan, Apple added a new feature that made manually repairing file permissions no longer necessary. File permissions are automatically repaired in OS X 10.11 and later.

  6. Reinstall the app. After checking the App Store to verify the app is still available, delete the problem app from your Mac and reinstall it from the App Store for a clean approach.

  7. Contact the app developer. Visit the app developer's website and see if there are any notes about compatibility with your version of macOS or OS X or other apps or services you use.