PDF FILE SUBMISSION

When Moodle is unable to view the submitted PDF file or shows the comment "**Generating the PDF**" but the student's PDF file is not displayed for grading or annotation, it indicates that the system is trying to process the file for viewing within the grading interface but encounters issues. Here are some common reasons why this might happen:

1) PDF Processing Issues

• Moodle relies on certain libraries (such as **Ghostscript** or other PDF processing tools) to render PDFs in the browser for grading and annotation. If these libraries are missing, outdated, or misconfigured on the server, Moodle may fail to generate the PDF for viewing.

2) File Corruption or Compatibility

• The student’s PDF might be corrupted or in a format that Moodle’s PDF renderer struggles to process. If the PDF file was created with non-standard settings, or if it includes complex elements (such as interactive forms, embedded media, or encryption), Moodle may not be able to display it properly.

3) Large File Size

• If the PDF is very large or contains many high-resolution images, Moodle might struggle to generate a preview in a timely manner, causing the “Generating the PDF” message to persist without showing the file.

4) Server Performance or Timeout Issues

• Moodle’s ability to generate and display PDFs depends on server resources. If the server is under heavy load, slow, or has low processing power, generating the PDF for annotation may take longer than expected or time out, resulting in the file not being displayed.

5) Browser or Client-Side Issues

• Sometimes, the problem can be on the teacher’s side, particularly related to the browser. If the browser does not support PDF rendering properly, or if there are issues with caching or plugins, the file may not be shown.

6) Incorrect Moodle Setup or Missing Plugins

• Moodle’s PDF annotation feature depends on certain settings and plugins (like **PDF annotation** or **assignment submission plugins**). If the Moodle installation is not configured correctly or required plugins are missing, it could cause problems with generating the PDF for annotation.

7) Permissions or Security Settings

• Some PDFs might have security settings, such as password protection or restrictions on editing, which could prevent Moodle from properly processing the file for display in the grading interface.

8) Unsupported PDF Features

• Certain PDFs may contain advanced features (e.g., multimedia content, dynamic elements, or digital signatures) that Moodle’s built-in PDF renderer cannot handle, leading to a failure in generating the viewable PDF.

Troubleshooting Steps

To resolve the issue:

1. Check Server Logs: The system administrator can review server logs to identify any errors during the PDF generation process.

2. Verify PDF Format: Ensure that students are submitting standard, non-encrypted PDFs with basic content.

3. Test on Different Browsers: Sometimes a different browser may display the PDF correctly if it’s a client-side issue.

4. Reduce File Size: Ask students to submit smaller PDFs to avoid performance issues.

Addressing these issues should allow the system to properly generate and display the student's PDF submission for annotation and grading.

WHAT CAN THE STUDENT DO TO PREVENT THIS ERROR?

Saving a PDF as a **flattened** PDF removes any interactive elements like forms, layers, annotations, and embedded multimedia, ensuring that it becomes a static document. Here's how students can save their PDFs as flattened PDFs using common tools:

1) **Adobe Acrobat**

Step 1: Open your PDF in Adobe Acrobat.

Step 2: Click on the **File** menu and select **Print**.

Step 3: In the print dialog box, choose **Adobe PDF** or **Microsoft Print to PDF** as the printer.

Step 4: Click **Print** and then choose where to save the new flattened PDF.

Step 5: The new file will be saved without any interactive elements.

2) **Microsoft Word**

   If the document was created in Word and saved as a PDF, you can flatten it during the conversion process.

Step 1: Open your Word document.

Step 2: Click **File** → **Save As**.

Step 3: Choose the location where you want to save the file.

Step 4: Under the **Save as type** dropdown, select **PDF**.

Step 5: Before saving, click on **Options** and ensure that **Document structure tags for accessibility** is **unchecked**.

Step 6: Click **Save**. This will generate a static (flattened) PDF.

3) **Google Docs**

Step 1: Open your document in Google Docs.

Step 2: Click on **File** → **Download** → **PDF Document (.pdf)**.

Step 3: This will download a static (flattened) PDF file without any interactive elements.

4) **Mac Preview**

Step 1: Open the PDF in Preview.

Step 2: Click **File** → **Export as PDF**.

Step 3: Choose a location and save the file. This will flatten any annotations and forms in the PDF.

5) **Online PDF Flattening Tools**

   There are several online tools available that allow you to flatten PDFs. One example is **Smallpdf**.

Step 1: Visit [Smallpdf.com](https://smallpdf.com/).

Step 2: Upload your PDF.

Step 3: Choose the "Compress PDF" option, which flattens the document during the process.

Step 4: Download the new, flattened PDF.

6) **PDF-XChange Editor (Windows)**

Step 1: Open the PDF in **PDF-XChange Editor**.

Step 2: Click on **File** → **Print**.

Step 3: In the print dialog, choose **Microsoft Print to PDF** as the printer.

Step 4: Click **Print**, then choose a location to save the flattened PDF.

Why Flatten PDFs?

Flattening ensures that the document is treated as a simple image or text file without interactive features like forms, comments, or multimedia. This helps ensure compatibility with platforms like Moodle, where more complex PDF elements might not render correctly.

Using these methods, students can save their documents as flattened PDFs to prevent issues when submitting through Moodle or similar platforms.

Reference:

Moodle. (n.d.). PDF annotation. MoodleDocs. https://docs.moodle.org/310/en/Assignment_activity 

Moodle. (n.d.). PDF annotation. MoodleDocs.https://moodle.org/plugins/mod_pdfannotator