Where Is Machine. Config?

You can run this in powershell:

[System.Runtime.InteropServices.RuntimeEnvironment]::SystemConfigurationFile

Which outputs this for .net 4:

C:\Windows\Microsoft.NET\Framework\v4.0.30319\config\machine.config

Note however that this might change depending on whether .net is running as 32 or 64 bit which will result in \Framework\ or \Framework64\ respectively.

In order to be absolutely sure, slap a Label on an ASP.NET page and run this code:

labelDebug.Text = System.Runtime.InteropServices.RuntimeEnvironment.SystemConfigurationFile;

I believe this will leave no doubt!

It semi-depends though... mine is:

C:\Windows\Microsoft.NET\Framework\v2.0.50727\CONFIG

and

C:\Windows\Microsoft.NET\Framework64\v2.0.50727\CONFIG

1. Open Windows Run command. Shortcut=> windows key + r
2. Type "microsoft.net" - MS .Net folder opens up
3. Open "Framework"/"Framework64" folder(based on your processor).
4. Select specific FW version folder e.g. "v4.0.30319"
5. Open config folder
6. Machine.config will be available there. Cheers.

C:\Windows\Microsoft.NET\Framework\v2.0.50727\CONFIG

In your asp.net app use this

using System.Configuration;
Response.Write(ConfigurationManager.OpenMachineConfiguration().FilePath);

This is a late reply, but if anyone is still looking to open machine.config and view/update configs, here's an example with IIS config using powershell

$machineConfig = [System.Configuration.ConfigurationManager]::OpenMachineConfiguration()

$deployment = $machineConfig.GetSection("")

$deplyment.Retail = $true

$machineconfig.save()

You can run this in powershell: copy & paste in power shell [System.Runtime.InteropServices.RuntimeEnvironment]::SystemConfigurationFile

mine output is: C:\Windows\Microsoft.NET\Framework\v2.0.50527\config\machine.config