Updating Dolibarr is essential to benefit from new features, security patches, and performance improvements. However, it’s not uncommon for users to encounter an HTTP 500 Internal Server Error right after an update. This type of error can be intimidating because it typically indicates a server-side issue without providing much detail on the surface. In this in-depth guide, we will explore the causes of the Error 500 in Dolibarr after an update, how to diagnose it, and step-by-step solutions to get your ERP system back up and running.

Table of Contents

  1. Understanding the HTTP Error 500

  2. Typical Scenarios That Trigger Error 500 After a Dolibarr Update

  3. Checklist Before Starting Troubleshooting

  4. Locating Error Logs

  5. Common Causes and Fixes

    • PHP Version Incompatibility

    • File Permissions

    • Missing or Corrupted Files

    • Deprecated Modules

    • Configuration Errors

    • Database Migration Failures

  6. Using Developer Tools for Diagnostics

  7. Recovering from a Failed Update

  8. Safely Rolling Back an Update

  9. Best Practices to Avoid Error 500 in Future Updates

  10. Summary and Final Recommendations


1. Understanding the HTTP Error 500

The HTTP 500 error is a generic response from the web server indicating that something has gone wrong on the server-side, but the server cannot be more specific. In the context of Dolibarr, this often points to issues with PHP execution, misconfigurations, or broken code.

Because the error is general, debugging it requires a methodical approach, checking logs and configurations to pinpoint the problem.


2. Typical Scenarios That Trigger Error 500 After a Dolibarr Update

Several issues may lead to a 500 error right after updating Dolibarr:

  • The server runs an incompatible version of PHP for the updated Dolibarr

  • File permissions change during upload or extraction of the update

  • One or more files did not transfer correctly (corruption or missing files)

  • Custom modules or old third-party modules are not compatible with the new version

  • The update did not fully complete, leaving the database partially migrated

Understanding these scenarios helps in narrowing down the diagnosis.


3. Checklist Before Starting Troubleshooting

Before diving into logs and configuration files, make sure:

  • You have a backup of your database and Dolibarr files

  • Your update process was followed according to official documentation

  • No simultaneous users were active during the update

  • The update process included the /install directory (sometimes mistakenly excluded)

Having these elements ready will streamline your debugging process.


4. Locating Error Logs

To diagnose a 500 error, access to error logs is essential. Here are key locations:

Apache or Nginx Logs

Depending on your web server, the log files are usually located in:

  • Apache: /var/log/apache2/error.log

  • Nginx: /var/log/nginx/error.log

PHP Logs

If PHP has its own log configured:

  • Check php.ini for error_log path

  • Or find them at /var/log/php/phpX.X-fpm.log (for PHP-FPM)

Dolibarr Logs

Dolibarr also keeps its own logs:

  • Check /documents/dolibarr.log

  • Enable $dolibarr_main_prod = 0; in conf.php to see errors directly in the browser


5. Common Causes and Fixes

PHP Version Incompatibility

Dolibarr versions are developed for specific PHP versions. Running it on an outdated or too new version can cause fatal errors.

Fix:

  • Check Dolibarr compatibility matrix on the official website

  • Switch to a supported PHP version using update-alternatives or your web panel

  • Restart the web server after changing PHP versions

File Permissions

Incorrect permissions may prevent PHP from executing certain scripts.

Fix:

chown -R www-data:www-data /var/www/dolibarr
find /var/www/dolibarr -type d -exec chmod 755 {} \;
find /var/www/dolibarr -type f -exec chmod 644 {} \;

Adjust www-data to your actual web server user.

Missing or Corrupted Files

This occurs when the update process is interrupted or incomplete.

Fix:

  • Re-upload Dolibarr source files (excluding conf.php and /documents)

  • Make sure .htaccess and all PHP files are included

  • Verify MD5/SHA checksums if available

Deprecated Modules

Old or custom modules may conflict with updated core code.

Fix:

  • Rename or move old modules temporarily out of /htdocs/custom

  • Check if the error goes away

  • Update or rewrite outdated modules

Configuration Errors

Improper conf.php settings can break functionality after updates.

Fix:

  • Open /htdocs/conf/conf.php

  • Validate paths, URLs, and DB credentials

  • Re-run the installation wizard if necessary via /install/

Database Migration Failures

Sometimes the update doesn’t complete database schema updates.

Fix:

  • Navigate to /install/

  • Follow the upgrade wizard to complete migrations

  • Check the llx_const and llx_version tables in the database


6. Using Developer Tools for Diagnostics

If log access is limited, you can enable developer mode in Dolibarr:

$dolibarr_main_prod = 0;

This allows PHP errors to be shown directly in the browser—useful for identifying syntax errors or missing includes.

Also, use tools like:

  • Xdebug for PHP step debugging

  • Browser developer tools to monitor HTTP headers and JavaScript errors

These tools complement log-based diagnosis.


7. Recovering from a Failed Update

If the update failed and broke your instance, follow this approach:

  1. Restore files from your backup

  2. Restore the database from the backup

  3. Try the update again, but:

    • Clear browser and server cache

    • Ensure no modules or customizations interfere

If you use Git for version control, you can also roll back easily using:

git checkout [previous-stable-tag]

8. Safely Rolling Back an Update

Rolling back is not always ideal but may be necessary in critical scenarios.

Manual Rollback:

  1. Replace updated files with your pre-update backup

  2. Restore pre-update database snapshot

  3. Confirm rollback worked by accessing the UI and checking system version

Git-Based Rollback:

If you use Git:

git checkout tags/14.0.5

Make sure to match your database version with the codebase.


9. Best Practices to Avoid Error 500 in Future Updates

Preventative measures make all the difference:

  • Always perform updates in a staging environment first

  • Back up files and databases before any major change

  • Avoid using outdated modules

  • Read release notes before updating

  • Use version control (like Git) for custom code

Following these practices reduces the likelihood of fatal errors.


10. Summary and Final Recommendations

Encountering an Error 500 in Dolibarr after an update can be daunting, but it's rarely unsolvable. Most problems stem from PHP incompatibilities, incomplete updates, or configuration issues.

By systematically checking logs, verifying permissions, ensuring compatibility, and restoring backups, you can resolve the issue and prevent it from happening again. Always approach updates with preparation: test, back up, verify—and you’ll save hours of recovery time.

Stay informed, follow Dolibarr community discussions, and use a methodical approach for smoother update experiences.