How can I get a restricted Asset Allowed File Type upload to accept RTF files I have an Asset field for front end users to upload asset files. I prefer to use the 'Restrict allowed file types?' option. However I do not see a choice for Rich Text Format (RTF). I have 'Word' checked, amongst others, but RTF is still rejected. Is there a way to amend this so users can submit RTF files? I am using the Sprout Forms plugin if it matters.
Does this help you? It'll let you add additional file extensions that are allowed to be uploaded.

http://buildwithcraft.com/docs/config-settings#allowedFileExtensions