NIK Collection 5 Version 5.0.5 x64 (5.3.0) update

Did you ever resolve the problem as I am experiencing much the same. Nothing visible to open the software in file manager, but visible in add and remove programs and in CCleaner. However the program is not able to be removed by either due to a glitch in the removal software. And as you found trying to reinstall is met with a message telling you the program already exists.