Attempted to access an unloaded appdomain. (Exception from HRESULT: 0x80131014)

Problem:

Using MVC 5 application and the namespace System.DirectoryServices.AccountManagement.
I kept getting this error intermittently running my app.  Looks like an issue in ADSI which is a bit buggy. 

Solution:

Tofumaster's suggestion of adding the domain string to the principal context seems to have done the trick for me. 

instead of

PrincipalContext ctx = new PrincipalContext(ContextType.Domain);

do this

PrincipalContext ctx = new PrincipalContext(ContextType.Domain,"MyDomain");

Source:

1. http://stackoverflow.com/questions/6605666/querying-active-directory-from-mvc-result-in-attempted-to-access-an-unloaded-ap
2. http://forums.asp.net/t/1697428.aspx?Querying+Active+Directory+from+MVC+result+in+Attempted+to+access+an+unloaded+appdomain+Exception+from+HRESULT+0x80131014+
3. http://stackoverflow.com/questions/5895128/attempted-to-access-an-unloaded-appdomain-when-using-system-directoryservices