Home > Moodle Activities & Resources > Assignment Activity (File Submission) > Troubleshooting: Assignment Grading Blank Preview
Sometimes when using the PDF annotator built into Assignment grading a student will submit a file and the preview will be blank, there may still be some ways to see what the student submitted or otherwise have that student save their work before submitting it to you.
Often when this happens the software the student used (such as Mac’s Preview app or Google Docs) may not save a fully compatible version of a PDF file and so Moodle doesn’t quite know what to do with it.