Seems you were on the right track.
Got it working normal by first associating .ico files with image glass
http://www.imageglass.org/
I then reset thumbnail and icon cache with this ...

Well, I'm pretty sure I know what the problem is. Or at least some of which it pertains to.
It is the file association with windows photo. However, it seems that when these files were associated...

Thanks for the response.
Well, I looked into your solution. Seems these don't work.
Although I should mention that I have these files backed up on a separate local network drive (Asus Router using...

Well, new install with Windows 10. I noticed while viewing my .ico files the thumbnails are corrupted.
I tried rebuilding the icon cache as well as purging the thumbnail cache.
Not sure whats left...