I'm getting a handful of student submissions that, in Speedgrader, show the following message: "This file contains HTML and cannot be previewed. Please download to view." However, when I try to download the file, I am unable to. I had a student share her screen with me to see if there was some kind of user error (uploading the wrong kind of file, or perhaps pasting the url of their Google doc instead of the file itself), but I didn't see anything out of the ordinary. While this is only affecting a small number of my students, I've had another teacher report that about 30% of her student submissions look this way.
I've looked for an answer, but all I've seen are a couple unanswered posts (including one where a moderator closed the thread because there wasn't much discussion on it).
I'd like to "third" this topic (if that's a thing!). We are getting it randomly from students in the class - there doesn't seem to be a particular pattern to it. Students get it when they need to upload a file - usually from their Google Drive, but it could also be a screenshot. Its very frustrating for the students. Help!
I will say that since I switched to using the Google Cloud Assignment tool, I haven't had a problem, so perhaps that can be a temporary workaround while we wait on Canvas to work out the glitches.
I am having the same trouble. The problem started with submissions from Friday. Submissions from the beginning of the week opened without a problem.
For our district, the issue was arising with documents being submitted from Google Drive. Interestingly, when students upload a file for an assignment, there are THREE different Google Drive tabs AND a Google Doc tab to choose from. I ran some experiments with my students and found that the "First Google Drive" tab or "the Google Drive on the left" worked the most reliably. I gave my students some quick & easy points for participating in the repeat submissions - they seemed to like that part.
Your mileage may vary!
Just as a way of trying to contribute to a workable solution (because I have yet to see any official response or fix), in addition to switching to the Google Cloud Assignment (which has it's own drawback, as I haven't seen Canvas mark assignments with no submission as "missing"), I had one student attach a pdf of his work as a comment on an assignment, and I was able to view his work that way. Another teacher that I work with changed all of her assignments to "text box entry" and had students copy and paste from their docs into the text box Canvas provides.
I admit to being frustrated by this process, as we have been using file uploads for Canvas work for years with no problem until this year.
I am glad I am not alone in seeing this problem crop up. This is my 6th year using canvas, and I have not encountered this problem until this year. It seems to be becoming more prevalent as the weeks go on.
My district is also having this problem. Teachers are reporting 5-6 student submissions per class are showing this error. File types are .HEIC .JPG and .PNG. A response would VERY much be appreciated.