How can I get rid of the notification that a Mac App store app which is not installed on this machine wants to update

Question

A long time ago (and on another machine) I bought a Mac App Store app (EventScripts) which is still available in the store.

I now have a new iMac (with macOS Mojave) where I haven't installed this app. However the Mac App Store on this app always notifies me that it wants to update this app. Here a screenshot from the "Updates" pane in the Mac App Store on this iMac:

How can I get rid of this notification (whileof course keeping the valid update notifications for other apps)?

---

More info:

The app is definitely not installed, because it does not appear in the /Application folder,

Strangely though, when I search for the app in the Mac App Store I get not a "Get" Button, but an "Update" button:

I guess it has something specific to do with this app which for many years did not get updates, but now it suddenly does get an update.

Answer 1

This answer is initiated by a comment from @Allan pointing me to the macOS system command lsregister. After ssuing

/System/Library/Frameworks/CoreServices.framework/Versions/A/Frameworks/LaunchServices.framework/Versions/A/Support/lsregister -dump

I could see that EventScripts was listed as an application - with the path on an external backup volume!

So now I knew what the steps to cure the problem are:

1. Making sure that Launch Services does not look on the external backup drive for applications. For this I excluded the external drive from Spotlight (System Preferences -> Spotlight -> Privacy).

2. Finally reindexing the Launch Services database. I did this with

    /System/Library/Frameworks/CoreServices.framework/Versions/A/Frameworks/LaunchServices.framework/Versions/A/Support/lsregister -kill -r -v -all u,s,l
   

After restarting the machine EventScripts is now - voila! - gone from Mac App Store's Update pane.

Answer 2

One simple way to stop this would be to go ahead with the update and let it do what it wants to do. If it installs the app you can then remove it. The app could be in a different folder than applications. Have you tried searching for the app name using Spotlight search or a Finder Search? The update button in the App Store just says it thinks the app is on your machine.