Resolve the Drupal fatal error cannot redeclare format_size() quickly by removing duplicate modules, checking code conflicts, and clearing cache. Our Drupal Support Team is always here to help you.
Solve Drupal Fatal Error Cannot Redeclare format_size()
Seeing Drupal fatal error cannot redeclare format_size() on your site can be frustrating, especially when it suddenly disrupts everything. This happens when the format_size() function in Drupal gets declared more than once, leading to a direct conflict. Let’s go through the practical ways to resolve this problem without wasting time.
Why This Error Appears
The message usually looks something like this:
Fatal error: Cannot redeclare system_requirements() (previously declared in /modules/system/system.install:12) in /modules/modules/system/system.install on line 299<c/ode>This occurs because multiple copies of the same module or conflicting code are present inside your Drupal installation. As a result, the format_size() function ends up being loaded more than once.
How to Resolve Drupal Fatal Error Cannot Redeclare format_size()
Instead of going in circles, here’s what you need to check and correct step by step:
1. Look for Duplicate Modules
First, scan your Drupal installation for duplicates. The error is common when more than one copy of the same module exists. You should carefully review:
- The modules/ folder
- The sites/all/modules/ folder
When you find duplicates, delete the extra folders immediately.
2. Review for Duplicate Code
Next, check your custom code, theme files, and any contributed module files. Ensure that format_size() is not being declared in multiple places. If you see more than one definition of the function, remove the unnecessary ones.
3. Verify Contributed Modules
If you are running contributed modules, confirm that you are not including the same module more than once. Also, avoid mixing different versions of the same module, as that can easily trigger the Drupal fatal error cannot redeclare format_size() issue.
4. Inspect Your Custom Code
If you have added your own custom code, make sure you are not accidentally redefining format_size(). Also, check if external libraries you integrated are redefining the function.
5. Scan Your Theme Files
Sometimes, the theme itself may contain function definitions. Open up your theme’s PHP files and confirm that they are not redeclaring format_size().
6. Clear Drupal Cache
Now, head into your admin panel. Navigate to:
Configuration → Development → Performance
Then, click on Clear all caches. Cached data often makes the error persist, so clearing it out is important.
7. Consider Module Loading Order
Another angle is the order in which modules load. Adjusting the load order may sometimes prevent the redeclaration conflict.
8. Check for File Naming Conflicts
Verify that there aren’t two files with the same name, both declaring format_size(). This situation often happens when a module and theme share identical file names.
9. Update Outdated Modules
If you are using old versions of contributed modules, upgrade them to the latest versions compatible with your Drupal core. Many redeclaration errors get resolved through updates.
10. Watch Out for Third-Party Libraries
If you are pulling in external libraries, double-check them for duplicate format_size() definitions.
11. Debug if Needed
In case the source remains unclear, enable debugging with debug_backtrace() or rely on Drupal’s built-in debugging tools to see exactly where the redeclaration is occurring.
12. Ensure Database Health
Although rare, database corruption may also lead to unexpected errors. Keep your Drupal database clean and healthy to avoid such issues.
[If needed, Our team is available 24/7 for additional assistance.]
Conclusion
The Drupal fatal error cannot redeclare format_size() is almost always linked to duplication, be it modules, code, or libraries. By systematically checking duplicates, clearing cache, updating modules, and debugging if necessary, you can eliminate this error and restore your site’s stability. Always remember to take a backup before making changes, especially when editing core files or contributed modules.
