Jesse,
You need these: (in the “portals” folder have only folders of “0”, “0-System” and ”_default”) so don’t delete them.
On my development machine I have done some testing with 7.3, which included creating and deleting portals. I have not had any problems with the creation/deletion of portals with the exception of remnant folders left in the root from deleted portals. This is likely a bug, but I haven’t had adaquate time to replicate the issue. All that will happen with the remnant folder is you won’t be able to create a new portal with the same name as the folder.
RE: “The one I thought it was successfully done; has created a folder in the root level of the website, but the contents are not DNN files” Without actually looking at these with my own eyes, I’m not sure what these are and I don’t want to guess.
RE: “Can I delete those useless folders?” It’s really difficult without knowing with certainty what these folders are and how they got there. If they are in fact remnants of old portals on the root and not in the portals folder and not referenced in the database it may be possible to delete them. I have no idea what these folders are so giving advice is very difficult.
You can always rename what you think are useless folders with a prefix or suffix of ZZZ. If you break DNN you can then always restore them back to the original names. Just be sure these are not referenced in the database.
Sorry… maybe not a very complete advice, but it is sometimes difficult to know what’s going on without actually seeing the problems.
Regards
Mike