A dump that stops partway.
HOW TO TELL
Open the SQL file in a text editor and look at the end. A complete dump ends cleanly. A truncated one stops mid-statement.
Compare the file size against previous exports.
WHY IT HAPPENS
A timeout during export, most commonly with phpMyAdmin on a large database Memory exhausted during the export Disk space ran out The connection dropped during download
THE FIX
Use the command line. mysqldump has no execution time limit and handles large databases reliably.
With SSH access this is the correct method for anything substantial.
WITHOUT SSH
Export tables in groups rather than all at once Exclude large log tables, which are frequently most of the size and rarely needed Use cPanel partial backups rather than phpMyAdmin Ask us to produce a dump for you
WHAT HAPPENS IF YOU IMPORT A TRUNCATED DUMP
Some tables restore and others do not. The site half works, which is more confusing than a clean failure.
Drop everything and start again with a complete file.