Configuration system failed to initialize : vb.net c#

Solution :

Search your application’s product name inside "C:\Users \#Username#\AppData\Local" and delete user.config, then Start your app again.

There are some other special directories which are also contains the temp config files.

VB.NET Code : Label1.Text = My.Computer.FileSystem.SpecialDirectories.AllUsersApplicationData

Result is [w10 64-bit] = C:\ProgramData\Microsoft\WindowsApplication1\1.0.0.0

Using Environment…

Result is [w10 64-bit] = C:\ProgramData

Result is [w10 64-bit] = C:\Users\venice\AppData\Local

Result is [w10 64-bit] = C:\Users\venice\AppData\Roaming

Note : Results will be same if OS (W7 64-bit, w8 64-bit)

Source

If there is no user.config then also it throws this error.

Go through this article : The exception was configuration system failed to initialize.