Hi LJTR21,
Welcome to Microsoft Community. I'm Mosken, let me help you.
According to your description, I knew that you are modifying the default opening method of .ica files, and the type was not found when you modified the file type at that time, even if you have tried to reinstall the application. Is that right?
First, I suggest you try right-clicking the type of file > Properties*, then click "Change" in the image below, and then try to select your application, if your target application is not in the existing list, click "More apps" > "* Look for another app on this PC*", then navigate to your app installation path and select your app (.exe), and check “Always use this app to open ICA files", then OK.*
Also, have you checked that if there are any relevant settings in the app? I suggest you try it.
The above steps are provided based on the information I have learned so far, and hope that could help you a little. If the problem still exists, please provide us a full PSR from the beginning, through the whole process, and until the error message is displayed, so we can further investigate.
Best Regards,
Mosken-MSFT | Microsoft Community Support Specialist