As we transition to the new Hyland Community, some post links may be temporarily disrupted as we finalize redirects. We apologize for the inconvenience and are working to resolve this as quickly as possible. Details.
I cannot open a folder that anyone sends to me
Folders cannot be shared without permissions restriction. So you need at least read permissions over the folder in order to access it. If the folder is inside a Site, you need to be member of the Site.