Hi ... I got same problem .... Its very Urgent help me ... thanks in advance .. Error Details ... Startup URI: C:\Working Folder\S&OP System\WpfBrowserApplicationTest\WpfBrowserApplicationTest\bin\Debug\WpfBrowserApplicationTest.xbap Application Identity: file:///C:/Working%20Folder/S%26OP%20System/WpfBrowserApplicationTest/WpfBrowserApplicationTest/bin/Debug/WpfBrowserApplicationTest.xbap#WpfBrowserApplicationTest.xbap, Version=1.0.0.0, Culture=neutral, PublicKeyToken=251d351ee89460b3, processorArchitecture=msil/WpfBrowserApplicationTest.exe, Version=1.0.0.0, Culture=neutral, PublicKeyToken=251d351ee89460b3, processorArchitecture=msil, type=win32 System.ArgumentException: Value does not fall within the expected range. at System.Deployment.Internal.Isolation.IDefinitionAppId.EnumAppPath() at System.ActivationContext.CreateFromNameAndManifests(ApplicationIdentity applicationIdentity, String[] manifestPaths) at System.ActivationContext.CreatePartialActivationContext(ApplicationIdentity identity, String[] manifestPaths) at System.Windows.Interop.ApplicationLauncherXappDebug.Initialize() at System.Windows.Interop.DocObjHost.MS.Internal.AppModel.IBrowserHostServices.Run(String path, String fragment, MimeType mime, String debugSecurityZoneURL, String applicationId, Object streamContainer, Object ucomLoadIStream, HostingFlags hostingFlags, INativeProgressPage nativeProgressPage, String progressAssemblyName, String progressClassName, String errorAssemblyName, String errorClassName, IHostBrowser hostBrowser) ----------------------- PresentationHost.exe v4.0.40305.0 built by: Main - C:\WINDOWS\system32\PresentationHost.exe ntdll.dll v5.2.3790.4455 (srv03_sp2_gdr.090203-1205) - C:\WINDOWS\system32\ntdll.dll kernel32.dll v5.2.3790.4480 (srv03_sp2_gdr.090321-1244) - C:\WINDOWS\system32\kernel32.dll ADVAPI32.dll v5.2.3790.4555 (srv03_sp2_gdr.090718-1230) - C:\WINDOWS\system32\ADVAPI32.dll RPCRT4.dll v5.2.3790.4759 (srv03_sp2_gdr.100817-0343) - C:\WINDOWS\system32\RPCRT4.dll Secur32.dll v5.2.3790.4530 (srv03_sp2_gdr.090615-1611) - C:\WINDOWS\system32\Secur32.dll USER32.dll v5.2.3790.4033 (srv03_sp2_gdr.070228-0030) - C:\WINDOWS\system32\USER32.dll GDI32.dll v5.2.3790.4396 (srv03_sp2_gdr.081022-1212) - C:\WINDOWS\system32\GDI32.dll ole32.dll v5.2.3790.4750 (srv03_sp2_gdr.100723-0347) - C:\WINDOWS\system32\ole32.dll msvcrt.dll v7.0.3790.3959 (srv03_sp2_rtm.070216-1710) - C:\WINDOWS\system32\msvcrt.dll OLEAUT32.dll v5.2.3790.4202 - C:\WINDOWS\system32\OLEAUT32.dll mscoree