I have seen this issue on one of our Windows 10 machines. I don't know why this happens. For some reason, Windows suddenly removes the icon associated with the desktop icon and assigns a generic document icon.
The workaround is simple:
- Right click the desktop icon.
- Select Properties.
- Click on Change Icon.... Ignore a "Cannot locate..." error message if it is shown.
- Select "C:\Program Files\PixInsight\bin\PixInsight.ico"
- On the PixInsight Properties window, click OK.
I'll investigate why this happens.