Supported Submission Types
CoGrader is designed to grade Google Docs created directly in Google Classroom or attached from Google Drive. That said, we’ve added a new workflow that lets you manually grant access to unsupported files, like PDFs, so grading can continue without starting over.
Works:
Google Docs is created directly in Classroom or attached from Google Drive.
Doesn’t Work Automatically
Word documents (.docx)
PDFs
Handwritten or image uploads
Google Slides, Sheets, or Drawings
Files uploaded as attachments that are not Google Docs
When a student submits one of these unsupported file types, CoGrader will prompt you to take action instead of blocking grading entirely.
What You’ll See in CoGrader
If a student submits a PDF or another unsupported file, you’ll see this message in the Status column:
“Can’t access file. Click here to grant access.”
Granting Access to a File
This new flow allows you to manually select the student’s file so CoGrader can proceed with grading.
Step 1: Click the Error Message
Click “Can’t access file. Click here to grant access.” next to the student’s name.
Step 2: Select the Student Submission
A modal will open showing which submission needs access.
Click on Select Files.
Step 3: Choose the Correct File
You’ll see a Google Drive file picker.
Important:
Select the exact file the student submitted
If the student uploaded multiple files, make sure you choose the correct one
Selecting the wrong file can send you back into the same loop
Click Select once the correct file is highlighted. Ensure the exact file the student submitted is selected; if not, it won't work.
Step 4: Grading Starts Automatically
Once the correct file is selected, there is a green tick on the student's name, and CoGrader immediately begins grading. No extra steps are required.
If the wrong file is selected, there will be no green tick.
Step 5: Review and Approve as Usual
After grading finishes, you can:
Review feedback
Edit scores or comments if needed
Approve the grading like any other submission
Syncing and Export Notes
Pressing Sync after the PDF has been graded does not sync PDF submissions. Sync only refreshes Google Doc permissions. To sync the PDF submissions, you should delete them, then sync to restart the process.
When exporting back to Google Classroom:
Google Doc submissions export feedback normally
PDF submissions may not display feedback inside the Classroom document
For now, exporting submissions like this must be done manually using the Print all, CSV, or PDF methods.
Why This Happens
Common causes include:
Students uploaded files instead of creating Docs directly in Classroom.
Students uploaded multiple files, including the Google Doc, but the Google Doc is attached second, and CoGrader is picking up the other unsupported file.
A Word or PDF file was attached instead of a Google Doc.
Tip: When creating assignments in Google Classroom, advise the students to submit using “Add or Create → Docs” to make sure all student work is readable by CoGrader automatically.
Quick Fix
If students already submitted unsupported files:
Click the error message in CoGrader (“Can’t access file. Click here to grant access.”).
Select the file to give CoGrader access.
Grading happens automatically.
Other Common Issues
“Can’t grade. Change the permission settings of the document.”
If you see this, press Sync once (or multiple times). This often refreshes file permissions.
If that doesn’t help, make sure:
You’re signed into the correct Google account.
The student’s file is shared with Editor access.
Google Drive and Classroom APIs are enabled in your school domain.
Summary
Best practices for smooth grading:
Require students to submit Google Docs only.
Have them create files within Classroom, not upload from elsewhere.
Press Sync if you see any access or permission errors.
Avoid:
Word docs, PDFs, or handwritten submissions.
Assignments that allow multiple file types.