Scheduled Site Workflows Run Twice

ISSUE

Scheduled site workflows are unexpectedly running twice, or not running at all.

RESOLUTION

Remove and reinstall the Scheduler job, making sure it is only installed on one Web Front End server:

1. Go to: Central Administration > Monitoring > Job Definitions
2. Look for the "Nintex Workflow Scheduler" and delete all instances but one.

There will likely be more than one scheduler listed - there should only be one. Delete any that are not on Web Front End servers.

ADDITIONAL INFORMATION

This is generally caused by a duplication of the Nintex Workflow Scheduler timer job. If this is installed on more than one server in the Farm it will run duplicates of a workflow or often fail to run at all.