One way sync without deletion of files

[meet law]

Hello,

I have two folders on my external hard drive. I would like to compare these folders and add all the files that exist in folder A (but not folder B) to Folder B. I don't want any files from Folder B to be copied to Folder A nor do I want any files deleted from Folder B. Is there a way to do this?

[Plerry]

Use the Update sync variant.
This variant does exactly what you describe.
Make FolderA your left location and FolderB your right location.