This started happening with Type2Phone, an app from Houdah Software. Every time after I would update the app via the AppStore, Spotlight would no longer find the app (I use Spotlight for app launching). I contacted the developer, and following a series of steps, we found that what is happening is that somehow the updated app is having this attribute added to it:
kMDItemSupportFileType = ( MDSystemFile )
[This is the output of the mdls command]
This explains why Spotlight is no longer finding the app.
Now logically, he informed me that this command should remove the attribute:
sudo xattr -d com.apple.metadata:kMDItemSupportFileType /Applications/Type2Phone.app
But although the command executes, it doesn't remove the attribute! I.e.
mdls /Applications/Type2Phone.app/ | grep MDSystemFile
MDSystemFile as output.
I've run Disk Utility to check for directory damage, rebuilt permissions, etc. to no avail. The only solution is to rebuild the Spotlight index completely -- but the problem will recur with a new update.
Although it inexplicably only happened every time I updated Type2Phone, now it's happening when I update Tweetbot.
Any insights into this problem which is driving me batty?