How to Fix Joomla Upload Size Limit Errors
Capture the exact upload error and file size
Record the file size, upload feature, HTTP status, and Joomla/PHP message. Errors can originate in Joomla or an extension, PHP, the web server, a proxy, or the hosting platform. Knowing whether the request reaches PHP prevents changing upload_max_filesize when an upstream server has already rejected the body.
Compare PHP's two primary upload limits
PHP documents upload_max_filesize as the maximum uploaded-file size and post_max_size as the maximum POST body. post_max_size must be larger than upload_max_filesize for typical form uploads. If the POST body exceeds post_max_size, PHP may provide no normal uploaded-file data to the application, so Joomla cannot recover the missing request body.
Check the effective values used by the website
Use Joomla System Information/PHP information or the host's PHP configuration view to inspect the web runtime. CLI PHP can load a different php.ini. Also check whether the host enforces a maximum that a local .user.ini, php.ini, or control-panel setting cannot exceed. Change configuration through the provider's supported method.
Check Joomla and extension-specific limits
Media and upload extensions may enforce their own maximum size or allowed-type policy below PHP's ceiling. Joomla's Update screen also warns when an update package exceeds PHP upload_max_filesize or post_max_size. Raise only the application limit required for the intended workflow and retain MIME/type validation.
Check upstream request-body limits
A reverse proxy, CDN, WAF, load balancer, or web server can cap request size independently. If you receive a 413 response or PHP never logs the request, inspect that upstream layer. Align the limits so the public request path permits the intended size without making every endpoint accept arbitrarily large bodies.
Verify temporary storage and time limits
Uploads are staged in temporary storage before application processing. Confirm adequate disk space, a usable PHP upload temporary directory, Joomla's configured temporary path where applicable, and sufficient request/input time. Large files can fail for storage or timeout reasons even after the nominal byte limit is increased.
Retest and document the final limit chain
Upload a controlled file near the desired maximum and verify the entire workflow. Record the Joomla/extension limit, PHP upload_max_filesize, PHP post_max_size, and any web-server or proxy limit. Future hosting or PHP changes are much easier to diagnose when the effective limit chain is documented.
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