Safe to delete empty folders from c:\windows\assembly?
C:\Windows\Assembly folder is the Global Assembly Cache (GAC) used by .NET Run time.
Generally, it is advisable to use the .NET command gacutil ( https://docs.microsoft.com/en-us/dotnet/framework/tools/gacutil-exe-gac-tool) to manage the contents of this folder.
However, if you think, it has any empty folder, you can delete that. If you delete any non-empty folder, it might create the problem to run .NET based program on your machine.
Please note, you will need administrator rights to delete any content in this folder (even if its an empty folder).