I had this same thing happen a week or so ago and someone suggested updating to the latest version which was .8 After upgrading to that version my problem went away now it's back again. One of the main things I do is store PDF files in EN. I either scan them into the EN import folder or drag and drop the PDF into EN and it has worked perfectly until now. I get an error message that says "Unable to upload.... One or more attachments could not be uploaded. A copy has been saved to your local file system". I have attached a copy of this message as well.
I have closed out of EN and reloaded with the same result. Any incite or help would be appreciated. Thanks in advance. - Phil