My Drupal installs have been running pretty darn smooth for a year or two. Seems like since I upgraded from Drupal 5x to Drupal 6x, a lot of those little “issues” went away. But lately I’ve been seeing this message more and more often:
Attempting to re-run cron while it is already running
The first time I saw the “cron is already running” error I went into a Googlebating frenzy to try and resolve the issue. I found (too) many suggestions like changing cron semaphores in the Drupal system table, running MySQL repairs, and throwing shells at the moon. Finally I came across a comment hidden in a post at Drupal.org that is simple, and for me, has fixed the dreaded ‘Attempting to re-run cron while it is already running’ error message 100% of the time.
To fix the Attempting to re-run cron while it is already running error:
are you ready for this? Just Clear your cache!
Admin|Site Configuration|Performance|(scroll down) – and hit the Clear Cached Data button .. boom – problem solved..