Write entry to locked settings file?

Question

I have the following code which is supposed to get the current config file, add an entry to it and then write back the file. However, this is not working (see stack trace) due to the file being locked. Is there a way to release it before doing this? Or can I do this a different way?

Code:

System.Configuration.Configuration config = ConfigurationManager.OpenExeConfiguration(ConfigurationUserLevel.PerUserRoamingAndLocal); // Add an Application Setting.

config.AppSettings.Settings.Add("InputDirectory" + inputdirs.Count + 1, newinputdir);
config.AppSettings.Settings.Add("OutputDirectory" + outputdirs.Count + 1, newoutputdir);

// Save the changes in App.config file.
try
{
    config.Save(ConfigurationSaveMode.Modified);
}
catch (Exception e)
{
    Console.WriteLine(e);
}
Console.WriteLine("Config update successful.");
readConfig();

Error:

System.Configuration.ConfigurationErrorsException: An error occurred executing t
he configuration section handler for appSettings. ---> System.InvalidOperationEx
ception: ConfigurationSection properties cannot be edited when locked.
   at System.Configuration.SectionInformation.VerifyIsEditable()
   at System.Configuration.MgmtConfigurationRecord.GetConfigDefinitionUpdates(Bo
olean requireUpdates, ConfigurationSaveMode saveMode, Boolean forceSaveAll, Conf
igDefinitionUpdates& definitionUpdates, ArrayList& configSourceUpdates)
   --- End of inner exception stack trace ---
   at System.Configuration.MgmtConfigurationRecord.GetConfigDefinitionUpdates(Bo
olean requireUpdates, ConfigurationSaveMode saveMode, Boolean forceSaveAll, Conf
igDefinitionUpdates& definitionUpdates, ArrayList& configSourceUpdates)
   at System.Configuration.MgmtConfigurationRecord.SaveAs(String filename, Confi
gurationSaveMode saveMode, Boolean forceUpdateAll)
   at System.Configuration.Configuration.SaveAsImpl(String filename, Configurati
onSaveMode saveMode, Boolean forceSaveAll)
   at System.Configuration.Configuration.Save(ConfigurationSaveMode saveMode)
   at EmailParserWinService.Program.Main(String[] args) in c:\Users\kylec\Docume
nts\Visual Studio 2012\Projects\EmailParserWinService\EmailParserWinService\Prog
ram.cs:line 78

I also tried manually modifying the exe configuration using the following:

System.Configuration.Configuration config = ConfigurationManager.OpenExeConfiguration(ConfigurationUserLevel.PerUserRoaming); // Add an Application Setting.
XmlDocument doc = new XmlDocument();
doc.Load(@config.FilePath);

However, this creates a problem as it seems the location doesn't exist.

'System.IO.DirectoryNotFoundException' occurred in System.Xml.dll

UPDATE:

I am now using the following:

ConfigurationSection settings = config.GetSection("EmailParserWinService.Settings");
settings.SectionInformation.AllowExeDefinition = ConfigurationAllowExeDefinition.MachineToLocalUser;
config.Sections.Add("GENERAL_USER_SETTINGS", settings);
config.Save();

But it is somehow a null reference. Specifically, this line: settings.SectionInformation.AllowExeDefinition = ConfigurationAllowExeDefinition.MachineToLocalUser;

Somehow my settings variable (even though I defined it right above?) is coming back null. I think the problem is that I'm not pulling the correct section of code. Which section of these would contain the settings?

    [0] "system.data.dataset"   object {string}
    [1] "mscorlib"  object {string}
    [2] "system.data.sqlclient" object {string}
    [3] "connectionStrings" object {string}
    [4] "system.webServer"  object {string}
    [5] "appSettings"   object {string}
    [6] "startup"   object {string}
    [7] "runtime"   object {string}
    [8] "system.data.odbc"  object {string}
    [9] "system.data"   object {string}
    [10]    "configProtectedData"   object {string}
    [11]    "system.codedom"    object {string}
    [12]    "uri"   object {string}
    [13]    "system.runtime.remoting"   object {string}
    [14]    "satelliteassemblies"   object {string}
    [15]    "system.data.oledb" object {string}
    [16]    "assemblyBinding"   object {string}
    [17]    "system.data.oracleclient"  object {string}
    [18]    "system.windows.forms"  object {string}
    [19]    "system.diagnostics"    object {string}
    [20]    "windows"   object {string}