Mac App Store thinks I don't have any apps installed

Okay, I have the weirdest problem. All the apps in my 'Purchases' tab show either 'Install' or 'Download', most of the apps I currently have installed, but non the less it doesn't recognise them. This holds true for brand new apps (installed yesterday) and ones I've had since I installed ML. I'd really like to get the apps recognised, so that I can get updates for them.

I've scoured the internet far and wide and haven't even been able to find any similar problems.

I really wish someone has an answer :)

Update: Deleting and reinstalling an app has no effect. It shows installed at first, but switching tabs and coming back to 'Purchases' renders it back to 'Install'.

Update: `CKSoftwareMap: updateRequestBodyData:includeInstalledApps:includeBundledApps:conditionally:hadUnadoptedApps:waitUntilMapIsLoaded: timed out waiting for mdSemaphore``

This is the "culprit" from Console.app and seems to be dependent on Spotlight indexes. Still don't know what corrupts my spotlight indexes...

You'll want to focus on problems with either Spotlight finding the apps or perhaps an overall disk structure failure.

• Spotlight: How to re-index folders or volumes - HT2409
• Spotlight indexes wrong HD
• Using Disk Utility to verify or repair disks - HT1782

Unless you are going in and systematically modifying each app's receipt, the App Store should find apps using spotlight and correctly reflect the status assuming both the disk doesn't need repair and the spotlight index is current.

I'd like to add to the possible solutions… I had the same problem. Turns out I also had a Windows disk installed that I needed some files from. I kept seeing errors in system.log like "Error getting quotas for volume /Volumes/...".

I powered off, disconnected the Windows disk, and rebooted. Voila! App Store can now search for updates and identifies installed purchases under the "Purchases" tab.

I hope I can save someone time, this problem has been plaguing me for a few days now.