We've heard a few users have this problem, and its also a common issue with other apps across Windows 10 users, not just to our app. The truth is that we don't have a specific answer on how to solve this. It seems to be related to a corruption of the user profile data in the Microsoft Store. Some users have been successful in resetting the app. You can do this by going to the Windows 'All Settings', selecting 'Apps'. Then go to 'Apps and Features' and look for Index Cards, and click once on the item. Then go to Advanced Options and scroll down to 'Reset'. Clicking Reset will reset all the app data and hopefully its connection to the store. Warning: By doing this you will also lose your data. If you have data that you want to keep, you can use the advanced method described in the FAQ above about the Index Cards database. If this Reset does not work, you might try to uninstall and re-install the app. If that doesn't work, you might want to see if there is a corruption in your user profile with the store. You can figure this out by creating another account on your computer, and then try to install Index Cards again. If that works, then unfortunately there is an issue with your user ID. You might want to try to log out of the Microsoft Store and re-login. That might clear up any corrupted profile information. Failing this, at this point I would suggest reaching out to Microsoft support forums for more detailed help or do some searching on the internet. Some users have found command line solutions to this but it can be a bit complex but in our research this is not a problem with a simple common fix. Let's hope this is not happening to you!