Showing a modal dialog box or form when the application is not running in UserInteractive mode is not a valid operation

The full error message is

“Showing a modal dialog box or form when the application is not running in UserInteractive mode is not a valid operation. Specify the ServiceNotification or DefaultDesktopOnly style to display a notification from a service application.”

This is probably due to you using MsgBox(“so message here.”) for your web application. I learn that you can only use MsgBox for window form application.

So, the solution is to think of other way to display a message to the user.

Hide your source code at the browser when hit error

I got a little anxious and embarrassed to see my source code exposed at the browser when I got an error.

Managed to find out that this is due to some setting at the web.config. I just need to set debug to false.

<configuration>
  <system.web>
    <compilation debug="false" />
  </system.web>
</configuration>

Unexpected error 0×8ffe2740 occurred

I realized that this happened when I try to start IIS when Apache web services has started (from XAMPP). When I stop Apache, I can start IIS.

And, vice versa, if I have my IIS started, I can’t able to start Apache. Perhaps this is due to they have the same port.

So, if you encountered this error message, check if you have Apache running at that time