Known Issues in Canvas

Click on a link to view a Canvas known issue:

Text (.txt) Files in Canvas

It is not possible to download text files (.txt) that have been added to Canvas sites; it is only possible to view a text file in the document previewer. Other standard file types like .doc, .docx, .pdf, .ppt, and .pptx can be downloaded from Canvas by clicking on a blue file link, but text files cannot be downloaded. For this reason, we do not recommend adding text files to Canvas.

Periods (.) in “Restrict File Upload” List

Canvas won’t let students submit file-upload online assignments if there is a period (.) for an extension in the list of accepted file-types in the “Restrict File Upload” field. To stop this from happening, you must list files extensions without periods–doc, docx, pdf, etc. and not .doc, .docx, and .pdf.

Mime Type Issue in Firefox

There is Firefox-specific bug that can affect mime types for files. Older versions of Firefox can sometimes produce a mime-type error when uploading files to a website. When this happens for files uploaded to Canvas, the file does not render correctly in the Canvas previewer because the browser interprets it as another file type; consequently, users either see  a string of code in the previewer or do not see the magnifying-glass icon for previewing the file at all. Fortunately, this bug does not affect users’ ability to download files, just the ability to preview them, so anyone with access to a file in a Canvas site can download it by clicking on the file link even when the file preview is not working.

To fix this issue, you can do the following:

1. Check to see that you are using a supported browser version. Whether you are using Firefox or another type of browser, please note that you should always use a version of a browser that Canvas supports to avoid issues affecting older versions. Please consult this list to see the browser versions Canvas currently supports: 

If you are already using a supported browser version, please clear your browser’s cache. Here are instructions for how to clear a cache on a PC:

And here are instructions for how to clear a cache on a Mac:

Then, please close the browser.

2. Open the browser and log into Canvas at with your PennKey username and password. Then, drag your mouse over the Courses tab and select the course containing the affected file.

3. Click on Files and then delete the file presenting issue by following these instructions:

4. Upload the file again by following these instructions:

After you save the changes, please check to see if the file previews correctly. If it does not, please email us at so we can investigate further.

Lost SpeedGrader Comments in Firefox

We have learned about a new Firefox bug affecting SpeedGrader. When a Teacher, TA, or Grader uses the margin commenting feature for annotations in SpeedGrader with Firefox, they must click outside of the comment bubble on another area of the document in order for the comment to be saved. This has led to several cases where final comments are not being saved when the user navigates to the next student submission.

We recommend the following workaround for this issue:

  • If you must use Firefox with SpeedGrader, make sure to click out of the comment bubble onto another area of the screen when adding your final comment on a paper to ensure that it is being saved before navigating to the next student submission.

Also, please note that if you leave SpeedGrader open for a submission for a long time, you can also lose comments, even when working in supported browsers. While it might seem that this behavior is the same as the Firefox bug, please be assured that it isn’t. Rather, it is the intended behavior of SpeedGrader when it has been open for a submission for an extended period of time.

Timeout Issues in SpeedGrader

SpeedGrader has a session timeout of 60 minutes. When a Teacher, TA, or Grader opens a document in SpeedGrader, Canvas will save all annotations for the next 60 minutes. After 50 minutes have passed a pop-up warning appears with instructions on how to restart your session to ensure additional edits are saved.

SpeedGrader timeout messageFailing to restart your session may result in lost annotations so we recommend adhering to the warning to ensure all feedback is saved.

Video Comment in Peer Review Marked “Incomplete”

Video comments submitted for a peer review are marked “incomplete” if they don’t have accompanying text. To avoid this issue, students should add text to their video-comment submission for peer reviews (e.g., “This is my submission”).

TIFF Files Not Supported in Canvas

Canvas does not support TIFF files. For this reason, it is recommended that JPEG and PNG file types be used in Canvas, as most browsers (Firefox, Chrome, Safari, IE, etc.) and Canvas support these file types.

Grading History Not Displaying All Grade Changes

The Canvas grading history for a student’s assignment grade only shows the two most recent grade changes in the last 24-hour period. Any additional changes made in this period are not saved.

Can’t Message Students in “Concluded” Courses in Canvas


Red X over

Although the messaging option for “Concluded” courses (meaning, courses from past terms that exist in a read-only state) appears in the Canvas message-form, it isn’t possible to send messages to students in “Concluded” courses because these courses are no longer active, and students can only access them in a read-only state. If you intend to stay in-touch with students from a course after the term ends, we recommend asking if they would like to exchange email addresses.

Teachers and TAs in “Concluded” courses can message one another using the “Concluded” messaging option.

No Email Notifications for Courses in Future Terms, Just Push Notifications

Users do not receive email notifications for actions taken in courses in future terms. For example, if you are a student in a course that is set up in Canvas for Fall 2020, and it is currently Summer 2020, you will not receive email notifications if your instructor takes an action (e.g., creates an assignment). This issue occurs even for courses that are currently active but are technically associated with a future term (e.g., a Fall 2020 course that actually starts in Summer 2020). Users do receive push notifications for these type of actions, however. To learn more about push notifications, please see “Set Push Notifications”on this page (instructor information and student information). Our vendor is working on a solution for this issue, and any updates on it will be posted here.

No Quiz Statistics for Classic Quizzes with More than 100 Questions or 1,000 Attempts

Quiz statistics aren’t available for Classic Quizzes with more than 100 questions or 1,000 attempts (i.e., more than 1,000 quiz submissions from students for a single quiz). When you click on the Quiz Statistics link for a quiz that exceeds these maximum values for questions or attempts, the following message appears:

Cartoon panda crying and the message,

Please consult the “Canvas Quiz Item Analysis” document for more information on the benefits and limitations of Canvas quiz statistics.

As a workaround, you can view quiz statistics by downloading the CSV files in the Student Analysis and Item Analysis links. You can then upload the file to Excel, Google Sheets, or another spreadsheet and view the data in a much more user-friendly format.

“Session Expired” Message When Viewing a Public Canvas Site

A “session expired” message and a log-in prompt appear after several minutes of viewing the public version of a Canvas site either for users whose login data has been saved in Canvas from a prior session or for users who are logged into Canvas in another browser window.

There are two possible solutions for this issue:

1. Log out of Canvas and clear your browser’s cache before accessing the public version of a Canvas site. Here are instructions for how to clear your browser’s cache:

Clearing your cache on a PC

Clearing your cache on a Mac

2. Use Google Chrome’s “Incognito” mode if you want to remain logged into Canvas while viewing the public version of a Canvas site (more information on Google Chrome’s “Incognito” mode).

Since this issue only affects users who have access to a Canvas instance, anyone outside the University of Pennsylvania who is not associated with a Canvas instance should not experience this issue. If a public version of a Canvas site is accessed by someone at another institution that has a Canvas instance, they should follow either of the above suggestions to avoid seeing the time-out message and log-in prompt.

Points Display for Ungraded Surveys in Modules

Users have reported experiencing an intermittent issue affecting ungraded surveys added to modules. When this issue occurs, a point-value (e.g., “1 pts”) displays in the module listing for an ungraded survey that has been added to a module. Our vendor has confirmed that this issue only affects how ungraded surveys display in modules and has verified that ungraded surveys that this issue affects do not count toward the total course grade. Our vendor’s engineers are working on a resolution for this issue, and an update will be posted to this “Known Issues” entry when the issue is resolved.

50-User Limit for Collaborations

A maximum of 50 users can be added to a Collaborations Google Doc in Canvas. If there are more than 50 users enrolled in the course site, the Collaborations tool will display only the first 50 users alphabetically.

Hanging Indentations in DocViewer

There is an extra carriage return to the formatting for hanging indentations for documents displayed in the DocViewer that use unsupported fonts. This misformatting only affects how a document displays in the DocViwer and does not affect the file itself; when downloaded, the file displays the correct formatting. Our vendor is working on a fix for this issue, and an update will be posted to this “Known Issues” entry when it is resolved.

Gradebook-Export Name-Sorting Issue

When you export the Canvas gradebook, sort the export by any column other than the “Student” column (for example: the “Final Score” column), and the re-sort the export by the “Student” column, the second sort re-orders the rows alphabetically by students’ first names instead of by their last names. When a gradebook is exported, the file is sorted alphabetically by last name, so a re-sort of the “Student” column after another column has been sorted does not restore the file to the original sorting order. Our vendor is currently working on a solution for this issue. An update will be posted to this “Known Issues” entry when a solution has been implemented.

Post Final Grades for Muted Moderated Assignments before Unmuting

If a moderated assignment has been unmuted before a moderator posts final grades for the assignment, Canvas generates a notification that the assignment has been unmuted, but the grades and feedback on the assignment are still unavailable to students because the final grades have not be posted. For this reason, it is recommended that final grades for muted moderated assignments be posted before they are unmuted so that the notifications students receive about the assignment being unmuted will accurately reflect the availability of the assignment’s grades and feedback.

“i” Character Not Displaying in Document Previews (Chrome 64)

If a box icon appears in place of an “i” character when previewing a document in Canvas through Chrome 64, then Chrome 64 does not support this character in the font being used. Our vendor has confirmed that this issue should be resolved in a future Chrome release, but, until then, if you encounter this issue, the following workarounds are recommended:

Some Special Characters Count as Words in the Rich Content Editor

These symbols each count as a word in Canvas’s Rich Content Editor:

`  ~ $ ^ = + > <

If you are an instructor or TA, it is recommended that you take this restriction into consideration if you are asking students to follow a word-count limit. If students will need to use these symbols, please factor the approximately number of instances a student might need to use these symbols for the following types of activities:

  • Text-entry assignment submissions
  • Discussion posts
  • Essay questions for Canvas quizzes
  • Pages that students can edit

If you are a student, please take this restriction into consideration if you have been given a word-count limit for:

  • Text-entry assignment submissions
  • Discussion posts
  • Essay questions for Canvas quizzes
  • Pages that students can edit

“Export Failure” for Duplicate File Names

When a Canvas site contains files with the same name, an “export failure” occurs for course content exports. To fix this issue, a Teacher, TA, or Designer will need to delete duplicate files, or, for different files with the same name, they will need to rename all files except one.

Downloading .csv Files From Canvas

Safari users will need to change a privacy setting in their web browser to download a .csv files from Canvas. If the setting is not changes, the default format, after downloading, will be .txt.

To correct this, in Safari’s Preferences:

  • Choose Privacy
  • Website tracking
  • Uncheck “Prevent cross-site tracking”

Last Updated: 16 Sep 2022