Do you have message filters?

Yes I do for incoming emails to go to different folders but not for sending

Well it sounds like you do have an outgoing filter. That is when the error occurs.

Do you have a lot of filters?

Hi Matt I do have a lot of filters but they are all set for incoming emails. I haven't changed them for a long time and this problem started fairly recently

Is it then possible that one of your filters marked a message to be sent? And, with that, I'm out of questions. :)

@David, I am struggling here as well. I was of the understanding all details of filters was stored in the msgfilterrules.dat file in the account folder in the profile. However when I started looking yesterday I found that the filter description and actions do appear there. But do not appear to include the run on send or periodically.

name="new test Filter"
enabled="no"
type="17"
action="Stop execution"
condition="AND (filtaquilla@mesquilla.com#javascript,matches,\"Date()  < \\"date\\"\") AND (filtaquilla@mesquilla.com#javascript,matches,)"

If you could verify that is would be good because now I am doubting myself as I can not find this stored anywhere else either.

I am finding the same results. Puzzling.

Does that mean there's a setting I can change?

I suggest you disable your filters and see if the error message goes away. If it does, then you need to carefully revisit your filters to discern what may be causing the error.

I have disabled all the filters on my incoming messages and it is still happening, any ideas?