PHP: Division by Zero In /mainwp/class/class-mainwp-system.php on line 889

After upgrading to version 4.0.3 of the Dashboard, my error log started filling up with PHP warnings like the following every 15 minutes:

PHP Warning:  Division by zero in /home/username/public_html/mainwp/wp-content/plugins/mainwp/class/class-mainwp-system.php on line 889

I took a look at that line in the code:

$mins_between = 24 * 60 / $frequencyDailyUpdate; // mins

It looks like $frequencyDailyUpdate is set on the Global Options page, but wasn’t given a default value in the wp_options table when I updated.

I ran the following on the database and got an empty result:

SELECT * FROM wp_options WHERE option_name = "mainwp_frequencyDailyUpdate"

The fix appears to be to simply save the settings on the Global Options page; you don’t have to make any changes because the setting Daily Update Frequency defaults to “Once per day” in the UI.

Following that, the SQL query returned a value of “1” for frequencyDailyUpdate.