I'm running Craft 3 on a local windows machine, but every time I try to update certain plugins (or Craft itself) I get a message "Couldn't back up the database. How would you like to proceed".

The logs give the following:

[error][craft\controllers\UpdaterController::actionBackup] Error backing up the database: The shell command "mysqldump ..." failed with exit code 1.

(I've removed most of the error code for the actual query, let me know if that would be useful).

I'm aware there are well documented hurdles with mysqldump and localhost, but I've already tried the proposed solutions here, here and here.

The global (not local, though I've tried both) PATH env has been set with the root of my MySQL folder ("C:\wamp64\bin\mysql\mysql5.7.26\bin") and I've restarted my machine, server etc. but still get the same error. I've also confirmed mysqldump is running and available in a normal terminal.

I've also tried the official guide to get MAMP working, tweaked as best I could for Windows (though I'm far from experienced so could have done something wrong) and that did nothing either.

I'm running Windows 10 (if that helps).

Any idea what exit code 1 means?

EDIT: See the comments below, but I've almost cracked this. My remaining issue is that I can't find any examples of the my.cnf file. Doesn't seem to be present on any Craft installs I have access to (though only this one has this issue), which means I can't manually generate it and Craft seems to be failing to do so. Any ideas?

  • Try to increase max_allowed_packet in your MySQL Config and see if that helps.
    – Oli
    Jun 20, 2019 at 12:33
  • Nice idea, but didn't work. Tried increasing to 64MB and 512MB, still getting the same error. Jun 20, 2019 at 13:19
  • Are you able to execute mysqldump to connect to the same database and make a backup from the command line?
    – Brad Bell
    Jun 20, 2019 at 20:58
  • So I can run a normal database backup on the command line using something like: mysqldump --databases t_craft --single-transaction --set-gtid-purged=OFF --add-drop-database --triggers --routines --events --user=root --password > partial_database_backup.sql However, having just tried using the script from the error log, I get an error due to the inclusion of the "&&" symbol, which is stated to be "not a valid statement seperator in this version". Interesting, will dig into this, but if anyone has any ideas how to change that it would be much appreciated! Jun 21, 2019 at 8:03
  • Right, did some Googling and came across this issue; apparently the && error is just when running in Power Shell. I've tried again in cmd and received a different error: Could not open required defaults file: [filepath]\my.cnf; Fatal error in default handling. Program aborted! Jun 21, 2019 at 8:12

1 Answer 1


Following up on your last comment:

So I guess my final question is: how can I either manually create the required file (which is missing) or amend the query?

You can completely override Craft's default backup command by specifying it in the backupCommand config setting.

Craft will attempt to execute whatever is in there when it goes to perform a backup.

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