I had the same problem with an older machine on which I was running PSE 9. I followed the procedure attached from the noted thread and it seems to work fine now. The PSE is just a large file and takes a bit to download. I had the same issue with a few other apps and the noted procedure worked for those applications as well. Thanks, Allan! 🙂
The only situation where there might be a problem in this procedure is with an app that's been updated past usability in the OS X version being used and there is no "last compatible version" mechanism in the version of the App Store in the OS X version being used. The downloadable version would reflect the latest one which is not necessarily compatible with the older OS. I think this would apply to someone using OS X Lion 10.7 and the application to be re-downloaded has advanced past 10.7, as I don't believe the App Store in Lion has the "last compatible version" option, as that was introduced with Mountain Lion 10.8. I'm not sure about this, but something to keep in mind.
Thread:
Any updates on security certification App Store issue?
Procedure:
Allan JonesNov 13, 2015 1:54 PM
Re: Any updates on security certification App Store issue?in response to tw9jd5
Apple is not here, only end users like you, so no one can give an "official" answer.
However, within the last hour I was able to recover all my non-functional apps, including three from Aspyr and one from a small developer.
1) Do one app at at time "just in case."
2) Sign out of the Mac App store and quit the App Store app:
3) Delete the non-responsive app from your computer
4) Relaunch the the App Store app and sign in.
5) Click on the Purchases tab, then find the app you deleted. The button to its right should say "Install."
6) Click "Install."
7) Find the reinstalled app in your Applications folder and see if it launches,
That worked for all my problem apps and I am back to 100-percent function. I lost no saved data from the apps I restored.