OJS PDF Not Displaying: Why Readers Can’t Access Your Articles

Readers clicking on your published articles see "File not found" or a blank PDF viewer. This is more than an inconvenience—it directly impacts your journal's reputation, download statistics, citations, and indexing. If Google Scholar or other harvesters encounter these errors, your articles may be flagged or delisted.

What This Error Means #

When PDFs don't display in OJS, it usually means the system can't locate or serve the file. The article metadata exists, but the actual PDF file is missing, inaccessible, or the path is broken. This can affect all articles, specific issues, or random individual files.

Common Causes #

• files_dir path incorrect in config.inc.php
• File permissions blocking web server access
• Files physically missing (deleted, failed migration, backup restored incorrectly)
• Disk space full—new uploads silently failed
• Database records pointing to wrong file paths
• PDF.js viewer plugin misconfigured
• Corrupted .htaccess blocking file access
• CDN or caching issues serving stale responses

Quick Check #

First, verify your files_dir setting in config.inc.php points to the correct location and that directory exists:

[files]
files_dir = /var/www/ojs_files

Check if the folder has proper permissions (readable by web server). If you recently migrated or restored from backup, the files_dir may point to the old server path.

For a single missing PDF, the file may have been accidentally deleted or the upload originally failed silently.

Why This Error Is Serious #

PDF access issues have cascading consequences:

• Lost citations: Researchers can't access your articles to cite them
• Indexing problems: Google Scholar may delist articles it can't crawl
• Author complaints: Authors expect their published work to be accessible
• Reputation damage: Readers lose trust in unreliable journals
• Statistics loss: Downloads aren't counted if files don't load

If multiple articles are affected, the underlying issue needs immediate attention before it impacts your journal's standing with indexing services.

Our Solution #

We audit your file storage setup, verify database-to-file mappings, fix path configurations, and ensure proper permissions. If files are missing, we help recover from backups or work with authors to re-upload. We also check that your setup won't cause future indexing problems.

Altechmind Technologies specializes in OJS configuration, migration, and troubleshooting. View all OJS services →