Please make sure that the file you are trying to upload doesn't contain any special characters, symbols, or spaces within the file name. File names can only contain upper- or lowercase letters, numbers, underscores, dashes, and periods. File names cannot begin with a period.
If you receive the error "---Invalid extension" when trying to upload a file, you are most likely trying to upload a file type not supported by Yahoo! Web Hosting.
Our FTP servers also check to see if the file being uploaded has the correct file extension. For instance, if you have a .bmp image and change its file extension to .gif or .jpg, the file will be rejected. (To convert a .bmp image to a .gif or .jpg image, you'll need to use an image-editing program. See: How can I save my image in a different file size or format?.)
You may also experience problems when attempting to upload very large files. We suggest uploading files larger than 2MB.