Launchpad displays app icons until it fills up the display and then creates another page of icons you can access with a swipe, just like in iOS. If you don’t have a gesture-enabled input device, such as the Magic Mouse or Magic Trackpad, or a built-in trackpad, you can still move from page to page by clicking the page indicators at the bottom of the Launchpad. All those icons on a blurred, semi-transparent background take a lot of graphics horsepower to pull off. So, instead of building thumbnails of each application icon every time the app is launched or a page is turned, Launchpad maintains a database. It includes the app icons, their location in the file system, where they should display in Launchpad, and other information necessary for Launchpad to do its job.
When Launchpad Fails
About the worst that happens with Launchpad is that an icon for an app you deleted refuses to go away, icons don’t stay on the page you want them on, or icons don’t maintain the organization you created. Sometimes, when you create a folder of apps in Launchpad, the icons return to their original location the next time you open Launchpad. While a problem with Launchpad can be annoying, it’s never a catastrophic issue that can cause harm to your data or Mac.
How to Fix Launchpad Problems
Forcing Launchpad to rebuild its internal database fixes most of the problems you may encounter. When you delete the database and then restart Launchpad, it grabs information from the database and discovers that the file containing the database is missing. Launchpad then scans for apps on the Mac, grabs their icons, and rebuilds its database file. The method for forcing Launchpad to rebuild its database varies slightly depending on the version of macOS or OS X you have.
How to Rebuild Launchpad Database in OS X Yosemite (10.10) and Later
In addition to the Launchpad database, OS X Yosemite and later versions of the operating system also maintain a cached copy of the database kept by the system, which also needs to be deleted. The next time you open Launchpad, the app rebuilds the databases it needs. Launchpad may take longer than usual to launch the first time. When it does, the Launchpad display is in the default organization, with Apple apps shown first and third-party apps next. Rearrange the Launchpad apps to suit your needs.
How to Rebuild Launchpad Database in OS X Mavericks (10.9) and Earlier
Earlier versions of OS X don’t maintain a cached copy of the database, so the Launchpad rebuild process is shorter. Follow the same process as above through the deletion of the .db files (Steps 1 through 6) and restart the Mac.
