The app prompts to login, fails to start, or is damaged#
Your Mac indicates that the app is damaged and prompts you to login, or to delete and reinstall the app from the App Store
This scenario can occur if you have copied an app to another Mac, for example, instead of downloading it directly from the App Store.
Sign in with your Apple-ID
If your Mac asks you to sign in with your Apple ID right after you’ve launched the app, do so! This should immediately fix the problem in most cases, or at the latest, after a restart.
Delete the app, then reinstall it from the App Store
If the problem persists: Uninstall the app, and then reinstall it from the App Store.
The App Store indicates a repurchase is needed
Apps downloaded from the App Store are tied to the specific Apple ID they were purchased with. If the App Store indicates that you need to buy the app “again”, then it was indeed not purchased with the Apple ID you are currently using.
If you have changed your Apple ID in the past, the download should work again. If you changed your Apple ID only a few days ago, you might need to wait a bit longer for this solution to be effective, as Apple requires some time to update everything on their end. If you have created a completely new Apple ID instead, there’s no way to transfer purchases.
I was forced to implement a certain level of copy protection mechanisms because a large portion of my apps fell victim to piracy. Please don’t steal my apps.
Individual Assistance
If none of the mentioned solutions have helped and you can prove your purchase with a receipt, please contact me directly and refer to this article.