I received this error message when trying to upload a 30MB file for a product in Prestashop:

The uploaded file exceeds the "Maximum size for a downloadable product" set in preferences (2MB) or the post_max_size/ directive in php.ini (2MB).

Two megabytes seems a bit stingy! What if you need more space for something large like an e-book? Here's how to increase the file size limit:

1. Go to Administration > Preferences and change the maximum size for downloadable products here.
2. Try this next step if the first solution doesn't work. Use software like Filezilla to find uploader.php in the classes folder of your Prestashop site. Open it and change DEFAULT_MAX_SIZE from 10485760 to 1048576000.
3. And if that doesn't work, try this. Open your host's php.ini file (it's usually in public_html or www). Then look for upload_max_filesize and post_max_size. They should equal something like 50M (which means 50 megabytes). Increase them if necessary.