Answer - If you have followed the instructions, and your replication setup is not working, first elliminate the user error factor by checking the following: Is the master logging to the binary log? Check with SHOW MASTER STATUS. If it is, Position will be non-zero. If not, verify that you have given the master log-bin option and have set server-id. Is the slave running? Check with SHOW SLAVE STATUS. The answer is found in Slave_running column. If not, verify slave options and check the error log for messages. If the slave is running, did it establish connection with the master? Do SHOW PROCESSLIST, find the thread with system user value in User column and none in the Host column, and check the State column. If it says connecting to master, verify the privileges for the replication user on the master, master host name, your DNS setup, whether the master is actually running, whether it is reachable from the slave, and if all that seems ok, read the error logs. If the slave was running, but then stopped, look at SHOW SLAVE STATUS output andcheck the error logs. It usually happens when some query that succeeded on the master fails on the slave. This should never happen if you have taken a proper snapshot of the master, and never modify the data on the slave outside of the slave thread. If it does, it is a bug, read below on how to report it. If a query on that succeeded on the master refuses to run on the slave, and a full database resync ( the proper thing to do ) does not seem feasible, try the following: First see if there is some stray record in the way. Understand how it got there, then delete it and run SLAVE START If the above does not work or does not apply, try to understand if it would be safe to make the update manually ( if needed) and then ignore the next query from the master. If you have decided you can skip the next query, do SET SQL_SLAVE_SKIP_COUNTER=1; SLAVE START; to skip a query that does not use auto_increment, last_insert_id or timestamp, or SET SQL_SLAVE_SKIP_COUNTER=2; SLAVE START; otherwise If you are sure the slave started out perfectly in sync with the master, and no one has updated the tables involved outside of slave thread, report the bug, so you will not have to do the above tricks again. Make sure you are not running into an old bug by upgrading to the most recent version. If all else fails, read the error logs. If they are bi