It should be nice to throw exception error for uploading file errors (or other errors in save() or validate() function). Indeed, I changed my development environment recently and it was so awful to work on the fact that uploading file didn’t work anymore. To be able to know why it didn’t work I had to read the $_FILES variable and to get the error code which is not very intuitive. I try to implement my own exception error function but it doesn’t work. Because of that error (which was a miss of temporary folder) my form simply refreshed at every submit without sending any error or CHttpException like it would.