Mac App Store Update issue in Yosemite I have a big problem with updating my apps in the App Store. When I install an application, it doesn't appear as installed as you can see here:



I have all of these apps installed on my computer, and I installed Telegram for example just right now and even that is does not appear as installed.

So I can't update any of my applications, and this forced me to install all of them again!

As you can see, it always shows "No Updates Available":



I'm sure something is wrong with my Mac App Store, I tried to delete the App Store caches but that doesn't work. How can I fix this?
When I have had problems with the App Store, I have found that the boot volume was entered in the System Preferences -> Spotlight -> Privacy pane.  If the boot volume is included, it is EXCLUDED from the Spotlight indices, and the App Store uses those indices to determine what applications are installed.  

Once the volume is removed, and the indices updated (you have to wait...), the App Store started finding updates.