What kind of file formats are not supported?

Any type of file can be stored in Athento. However, for security reasons, some formats such as .EXE cannot be uploaded to the platform. Users can configure which file types are allowed in a space.

Although Athento can store virtually any file type, you should be aware that some functionality such as previewing may not be available for that file type. 

From here you can see the list of extensions that can be previewed in Athento.