Annoying popup

About 3 minutes after I reboot my computer I get the following popup:
"Either there is no default mail client or the current mail client cannot fulfill the messaging request. Please run Microsoft Outlook Express and set it as the default mail client". It only happens once. Outlook express is set as my default mail client. Can someone help or send me to a post where this has been addressed? thanx Jim B

Hi Jimbir,
Just a guess but do you have a spam filter set on your e-mail?
I get this occasionally when my virus checker is trying to send a message back to base to report new spam detected in the inbox or as it downloads intio OE. I just ignore it and the message gets sent as soon as OE loads.
Regards.

Yes, I have Norton antispam checking my email and it seems to work properly. Again, this only happens once after I boot my computer.

I think the way round it might be to get Outlook Express to load before Norton. Then it will have an e-mail client to use and won't complain.