I already posted a question about this issue in the AnswerHub a bit over a month ago, but, as I still hasn’t found a solution I thought about trying my luck here as well.
In summary, I get the the warning message below about 8000 times, and I need to get rid of the warnings, soon, but I have no idea what is causing them to pop up.
Shader … unknown by landscape thumbnail material, please add to either AllowedShaderTypes or ExcludedShaderTypes
You can take a look at the oriignal question in the link below
I would appreciate any help or advice regarding this issue.