Drupal 6 Cron.php not running - aggregator not updating

Version: Drupal 6.22

For whatever reason Cron will stop working occasionally on a site. The symptoms can vary, in some browsers it loads the custom 404 error page, and in IE it actually went to a white screen but the aggregator data was not being updated. When running cron manually from the Status Report page it simply says cron failed.

Solution:
First run Clear Cache from Admin -> Performance
Edit "common.inc" in the "/includes" directory.
On about line 2721 you need to change;


// Fetch the cron semaphore
$semaphore = variable_get('cron_semaphore', FALSE);


to
// Fetch the cron semaphore
//$semaphore = variable_get('cron_semaphore', FALSE);
$semaphore = FALSE;


Run cron again.
Now revert back to the old common.inc file.

Special thanks to Digital Edge Software & Consulting for the solution