Challenge:

Since so long back, we faced one problem in which when we open Sitecore installation wizard/Package Designer it was showing following error:

Server Error in ‘/’ Application.

Unable to load one or more of the requested types. Retrieve the LoaderExceptions property for more information.

Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code.

Exception Details: System.Reflection.ReflectionTypeLoadException: Unable to load one or more of the requested types. Retrieve the LoaderExceptions property for more information.

Source Error:

An unhandled exception was generated during the execution of the current web request. Information regarding the origin and location of the exception can be identified using the exception stack trace below.

Stack Trace:

[ReflectionTypeLoadException: Unable to load one or more of the requested types. 
Retrieve the LoaderExceptions property for more information.]
   System.Reflection.Module._GetTypesInternal(StackCrawlMark& stackMark) +0
   System.Reflection.Assembly.GetTypes() +105
   Sitecore.Install.Configuration.InstallerObjectFactory..ctor() +96
   Sitecore.Install.Configuration.InstallerObjectFactory..cctor() +21

[TypeInitializationException: The type initializer for 'Sitecore.Install.
Configuration.InstallerObjectFactory' threw an exception.]
   Sitecore.Install.Configuration.InstallerObjectFactory.get_Instance() +0
   Sitecore.Shell.Applications.Install.UIFactory.GetContextUri(Type type) +11
   Sitecore.Shell.Applications.Install.UIFactory.GetContextUri(Object instance) +19
   Sitecore.Shell.Applications.Install.Controls.ProjectView.UpdateContext() +80
   Sitecore.Shell.Applications.Install.Controls.ProjectView.SetSelection(String property) +57
   Sitecore.Shell.Applications.Install.Designer.OnLoad(EventArgs e) +178

[TargetInvocationException: Exception has been thrown by the target of an invocation.]
   System.RuntimeMethodHandle._InvokeMethodFast(Object target, Object[] arguments, SignatureStruct& sig, 
MethodAttributes methodAttributes, RuntimeTypeHandle typeOwner) +0
   System.RuntimeMethodHandle.InvokeMethodFast(Object target, Object[] arguments, Signature sig, 
MethodAttributes methodAttributes, RuntimeTypeHandle typeOwner) +71
   System.Reflection.RuntimeMethodInfo.Invoke(Object obj, BindingFlags invokeAttr, Binder binder, 
Object[] parameters, CultureInfo culture, Boolean skipVisibilityChecks) +261
   System.Reflection.RuntimeMethodInfo.Invoke(Object obj, BindingFlags invokeAttr, Binder binder, 
Object[] parameters, CultureInfo culture) +29
   Sitecore.Reflection.ReflectionUtil.InvokeMethod(MethodInfo method, Object[] parameters, Object obj) +45
   Sitecore.Reflection.ReflectionUtil.CallMethod(Type type, Object obj, String methodName, 
Boolean includeNonPublic, Boolean includeInherited, Boolean includeStatic, Object[] parameters) +87
   Sitecore.Reflection.ReflectionUtil.CallMethod(Object obj, String methodName, 
Boolean includeNonPublic, Boolean includeInherited, Object[] parameters) +43
   Sitecore.Web.UI.Sheer.ClientPage.OnLoad(EventArgs e) +191
   Sitecore.Shell.Web.UI.SecurePage.OnLoad(EventArgs e) +24
   System.Web.UI.Control.LoadRecursive() +50
   System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, 
Boolean includeStagesAfterAsyncPoint) +627

Solution:

After trying lot of things finally we found the solution. Basically under “/website/bin” folder “ITHit.WebDAV.Server.dll” was missing. We got it from other developer’s box for whom it was working fine and it fixed the issue!

I hope it will help you as well, when you are ready to send a deployment and at that same time Package Designer/Installation wizard is not working.

Happy Sitecoring! 🙂