Configuration System Failed to Initialize

Solution 1:

Make sure that your config file (web.config if web, or app.config if windows) in your project starts as:

<?xml version="1.0"?>
<configuration>
    <configSections>
        <sectionGroup name="applicationSettings" 
                      type="System.Configuration.ApplicationSettingsGroup, System, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089" >

            <section name="YourProjectName.Properties.Settings" 
                     type="System.Configuration.ClientSettingsSection, System, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089" 
                     requirePermission="false" />

        </sectionGroup>
    </configSections>
</configuration>

Note that inside the configuration element, the first child must be the configSections element.

In the name property on section element, make sure you replace YourProjectName with your actual project's name.

It happened to me that I created a webservice in a class library project, then I copied (overwriting) the config file (in order to bring the endpoints configuration) to my windows app and I started to have the same problem. I had inadvertently removed configSections.

it worked for me, hope it helps

Solution 2:

Delete old configuration files from c:\Users\username\AppData\Local\appname and c:\Users\username\AppData\Roaming\appname and then try to restart your application.

Solution 3:

Sometimes the Error occurs because a windows create a duplicate in the

C:\Users\App Data\Local\"You App Name"...

Just delete this folder and done. try it.

Solution 4:

If you've added your own custom configuration sections to your App.Config, make sure you have defined the section in the <configSections> element. I added the my config XML but forgot to declare the configuration section up top - which caused the exception "Configuration system failed to initialize" for me.

Solution 5:

I had this same problem with an MSTest class: Marlon Grech in his article says "the element has to be defined as the first element in the App.config."

So make sure that is the first element in under the element. I had put AppSettings first.