Thanks for your help. I have a subfolder in my application folder for astronomy applications. Pixinsight as I downloaded it came as a folder with the icon to open the app in that folder. I took the PixInsight folder out of my astronomy subfolder and left it intact in the main applications folder. That seems to have solved the problem. I assume updates are automatically placed in the PixInsight folder and that could not be found with it in the subfolder. Again thanks for the reply.
