I'm also having this problem, and I agree this is not a useful answer.
That's the problem with discussion forums that reward points, you get everyone and his brother rushing to answer questions even when they don't know the answer.
One of the "functional" problems I have is that this late 2013 iMac 10.11.6 has become quite sluggish over the last few months. This is why I was looking at the console. An error message that has repeated every 5 seconds, going back months on end, sounds a lot like something that could cause I/O bottlenecks.