There are occasions when applications that have been removed have stale links left behind in the Unity Dash. Though it is harmless, it is annoying to see them popup as results to searches in the dash when they are useless – creating a problem by taking up search results that could lead to what you’re searching for more quickly.
Removing them is fairly simple, but it can be easy to forget if you haven’t done it before – or at least not for a while.
Most of the links in the Unity Dash are stored in the /share/applications folder. However, depending on if the application was installed for just one user or for all users determines which folder the links are stored at. If the application was installed on the system for all users, you will have to use root access to remove them from the /usr/share/applications directory. If they were installed by a user strictly for that user, they will be in the .local/share/applications directory within that user’s home.
Make sure you empty your Trash after you delete the links. They will not be removed from the Dash until you do.