c# - Clickonce full trust app update failing with TrustNotGrantedException on Windows 8

Question

We have a winforms clickonce application in C# which is granted full trust and signed using a valid certificate.

The application runs fine and updates correctly on Windows XP, Windows 7. However, on a Windows 8 machine, it just fails to update. The application runs correctly though. However, the first update request to move up to a later version fails with: System.Deployment.Application.TrustNotGrantedException

The code failed after the call to ApplicationDeployment::CheckForDetailedUpdate() failed. Wondering why this could happen as the exact same code is running fine on all previous versions of Windows. Any help will be appreciated. Below is the relevant stack trace:

System.Deployment.Application.TrustNotGrantedException: User has refused to grant required permissions to the application.
   at System.Deployment.Application.ApplicationTrust.RequestTrust(SubscriptionState subState, Boolean isShellVisible, Boolean isUpdate, ActivationContext actCtx, TrustManagerContext tmc)
   at System.Deployment.Application.DeploymentManager.DetermineTrustCore(Boolean blocking, TrustParams tp)
   at System.Deployment.Application.DeploymentManager.DetermineTrust(TrustParams trustParams)
   at System.Deployment.Application.ApplicationDeployment.CheckForDetailedUpdate(Boolean persistUpdateCheckResult)
   at System.Deployment.Application.ApplicationDeployment.CheckForDetailedUpdate()

Answer 1

The only time I'd seen this stack trace was when I tried calling CheckForDetailedUpdate() without setting up the explicit trust before hand. After adding the code below, the update check worked.

// Setup the trust level
var deployment = ApplicationDeployment.CurrentDeployment;
var appId = new ApplicationIdentity(deployment.UpdatedApplicationFullName);
var unrestrictedPerms = new PermissionSet(PermissionState.Unrestricted);
var appTrust = new ApplicationTrust(appId) {
    DefaultGrantSet = new PolicyStatement(unrestrictedPerms),
    IsApplicationTrustedToRun = true,
    Persist = true
};
ApplicationSecurityManager.UserApplicationTrusts.Add(appTrust);

// Check for update
var info = deployment.CheckForDetailedUpdate();