Launchpad, the app launcher that Apple introduced with OS X Lion (10.7), was an attempt to bring a touch of iOS to the Mac operating system. Like its iOS counterpart, Launchpad displays all the apps you’ve installed on your Mac in a simple interface of app icons scattered across your Mac screen. A click on an app icon launches the app, letting you go straight to work (or play).
Launchpad is quite simple. It displays the app icons until it fills your screen, and then creates another page of icons that you can swipe to, just like on iOS. If you don’t have a gesture-enabled input device, such as a Magic Mouse or Magic Trackpad, or a built-in trackpad, you can move from page to page with a simple click of the page indicators at the bottom of the Launchpad.
So far it seems simple enough, but have you noticed how quickly Launchpad moves from page to page, or how quickly it launches when you first select the app? The launch speed is very impressive, even more so when you realize that all those icons on a blurry, semi-transparent background require a huge amount of graphics power.
How does Launchpad manage to race like a Kentucky Derby champion? Well, unlike the magnificent animals of Churchill Downs, Launchpad cheats. Instead of creating thumbnails of each app’s icon every time the app is launched or a page is turned, Launchpad maintains a database that includes the app’s icons, where the app is located in the system. files, where the icon should be displayed in Launchpad, plus some other data needed for Launchpad to work its magic.
When Launchpad fails
Fortunately, Launchpad glitches aren’t nearly as destructive as the ones at Cape Canaveral. For Launchpad, the worst that can happen is that an app icon you’ve deleted refuses to go away, icons don’t stay on the page you want them on, or icons don’t maintain the organization you’ve created. Or finally, when you create an app folder in Launchpad, the icons return to their original location the next time you open Launchpad.
In all Launchpad failure modes that I’m aware of, no damage is ever done to the Mac or any installed apps. Although Launchpad problems can be annoying, they are never a catastrophic problem that can cause damage to your data or your Mac.
The solution to Launchpad problems is to delete system and user data, so before proceeding make sure you have a recent backup.
Fixed issues with Launchpad
As I mentioned earlier, Launchpad uses a database to store all the information needed for the app to work, which means forcing Launchpad to rebuild its internal database can fix most problems encountered.
The method for rebuilding the database varies a bit depending on the version of OS X you’re running, but in all cases, we’re going to delete the database and then restart Launchpad. Launchpad will go to collect information from the database and quickly discover that the file containing the database is missing. Launchpad will search for apps on your Mac, grab their icons, and rebuild their database file.
How to rebuild the Launchpad database on OS X Mavericks (10.10.9) and earlier
- Quit Launchpad, if it’s open. You can do this by clicking anywhere in the Launchpad app, as long as you don’t click an app icon.
- Open a Finder window .
- You need to access the Library folder , which is hidden by the operating system. Once you have the Library folder open and visible in Finder, you can proceed to the next step.
- In the Library folder , find and open the Application Support folder .
- In the Application Support folder , find and open the Dock folder .
- You’ll find several files in the Dock folder , including one called desktoppicture.db , and one or more files that start with a dashed set of uppercase letters and numbers and end with .db. An example filename is FE0131A-54E1-2A8E-B0A0A77CFCA4.db . Grab all the files in the Dock folder with the dotted set of letters and numbers ending in .db and drag them to the Trash.
- You can then restart your Mac, or if you don’t mind a bit of work in Terminal, you can open the Terminal app, located in the /Applications/Utilities folder, and run the following command:
Killall Dock
Either method works fine. The next time you open Launchpad, the database will be rebuilt. Launching may take a bit longer the first time while Launchpad rebuilds its database, but other than that Launchpad should be good to go.
How to rebuild the Launchpad database in OS X Yosemite (10.10) and later
OS X Yosemite adds a bit of a wrinkle to Launchpad’s database deletion method. Yosemite and later versions of OS X also maintain a cached copy of the system-maintained database, which must also be deleted.
- Do steps 1 through 6 above.
- At this point, you have removed the .db files from the ~/Library/Application Support/Dock folder and are ready for the next step.
- Start Terminal, located in the /Applications/Utilities folder.
- In the Terminal window, enter the following:
default write com.apple.dock ResetLaunchPad -bool true
- Press enter or return to execute the command.
- In the Terminal window, enter:
Killall Dock
- Hit enter or return .
- You can now exit Terminal.
Launchpad has been reset. The next time you open Launchpad, the app will rebuild the databases it needs. Launchpad may take a little longer than usual to launch the first time, and the Launchpad screen will now be in its default arrangement, with Apple apps first and third-party apps second.
Now you can rearrange Launchpad to suit your needs.
