Sonar has generated an error

Hello all!

For the past few weeks I've been seeing this error message pop up on two of our clients.

Event ID: 74
Event Description: SONAR has generated an error: code 0: description: Definition Failure

This occurs after every definition update.

Near as I can tell the Sonar definitions are up to date and are getting downloaded properly to the client.  Most of the tech articles I've looked at seem like they're for if the Sonar definitions aren't getting downloaded to the client.

Not sure where to start looking for a solution at this point.  I'd rather avoid just blindly deleting registry keys and rebooting servers when I'm not exactly certain what's going on with this error message.

Thank you for your time.