ASP.NET in Chrome getting a strange focus_change nikkomsgchannel error
If you have Rapport software, try removing that.
I have just removed it and finally after weeks of those annoying messages when developing, they have disappeared.
You don't have to entirely remove the Rapport software.
You can restart your computer in safe mode (F8 when it restarts), and change the type of the files containing "RapportNikko" from dll to something else, say old.