Okay this is a huge issue/bug!
I just bought my 2015 Macbook yesterday and I made the mistake of deleting an app from launchpad (dragging and dropping to trash) while it was still open/probably open in the background.
The app is gone from the Finder but the icon stays in the Launchpad. When I click the icon it says app is in the trash. So I emptied the trash. Then when you click it again, a translucent question mark will appear over it. From this point, I've tried the following but nothing worked:
- Hold app icon till x appears. Try deleting. No response.
- Hold alt/option till icons jiggle. x will appear. Try deleting. No response.
- Reinstall apps through app store. Try clicking icon again. Question mark will disappear and app will launch. Now try deleting from Finder > Applications instead. Right click and move to trash or drag and move to trash. Icons will still remain!! (seriously?!) Click them again, question mark will appear over them.
- Do any of the above, but restart after. Problem persists.
At this point I was pretty disappointed with Apple's inconsistency. I'm also pretty ****** off that there is no place in system preferences where I can see what programs/drivers I have installed..... so much care and thought has been put into OSX... but there's still nothing for this? Windows seems to be miles ahead. Disappointing.
Anyway someone suggested the following solutions:
- Use App Zapper http://www.appzapper.com/
- Use Launchpad Manager http://launchpadmanager.com/
The 2nd one worked for me to get rid of the annoying icons that remain. Hope this helps someone. Also hope Mac actually integrates these features into OSX....
I have posted this same solution on a different thread.