Ever since I started using R18, I am no longer able to view the scene"preview image" thumbnails of c4d files. All I get is the standard c4d logo when using Windows explorer (on both win7 and win10 machines). Even projects saved with earlier versions of C4D now just show the c4d logo and have lost their associated preview image.
If I go into Projects>Info you can change the scene preview image to a custom one or the current viewport, but this still makes no difference.
I am using the latest 18.041, but this has occurred in all versions of R18 on my machines.
Not sure if this i Windows specific or not, so wondering if anyone else has this issue, before I file it as a bug to Maxon?