Works on my machine

Background task works now (only tested on desktop). Also fixed creating or linking a new account.

Author: golf1052

Signal-Windows/App.xaml.cs

@@ -132,15 +132,15 @@ protected override async void OnLaunched(LaunchActivatedEventArgs e)
         {
             string taskName = "SignalMessageBackgroundTask";
             bool foundTask = false;
-            BackgroundExecutionManager.RemoveAccess();
-            foreach (var task in BackgroundTaskRegistration.AllTasks)
-            {
-                if (task.Value.Name == taskName)
-                {
-                    backgroundTaskRegistration = task.Value;
-                    foundTask = true;
-                }
-            }
+            BackgroundExecutionManager.RemoveAccess("2383BenediktRadtke.SignalPrivateMessenger");
+            //foreach (var task in BackgroundTaskRegistration.AllTasks)
+            //{
+            //    if (task.Value.Name == taskName)
+            //    {
+            //        backgroundTaskRegistration = task.Value;
+            //        foundTask = true;
+            //    }
+            //}
 
             if (!foundTask)
             {
@@ -149,8 +149,8 @@ protected override async void OnLaunched(LaunchActivatedEventArgs e)
                 builder.TaskEntryPoint = "Signal_Windows.RC.SignalBackgroundTask";
                 builder.IsNetworkRequested = true;
                 builder.SetTrigger(new TimeTrigger(15, false));
-                builder.SetTrigger(new SystemTrigger(SystemTriggerType.ServicingComplete, false));
-                builder.SetTrigger(new SystemTrigger(SystemTriggerType.TimeZoneChange, false));
+                //builder.SetTrigger(new SystemTrigger(SystemTriggerType.ServicingComplete, false));
+                //builder.SetTrigger(new SystemTrigger(SystemTriggerType.TimeZoneChange, false));
                 builder.AddCondition(new SystemCondition(SystemConditionType.InternetAvailable));
                 var requestStatus = await BackgroundExecutionManager.RequestAccessAsync();
                 if (requestStatus != BackgroundAccessStatus.DeniedBySystemPolicy ||

Signal-Windows/Package.appxmanifest

@@ -21,21 +21,22 @@
         <uap:SplashScreen Image="Assets\SplashScreen.png" BackgroundColor="#2090EA" />
       </uap:VisualElements>
       <Extensions>
-        <Extension Category="windows.backgroundTasks" EntryPoint="Signal_Windows.RC.SignalBackgroundTask">
-          <BackgroundTasks>
-            <Task Type="systemEvent" />
-          </BackgroundTasks>
-        </Extension>
         <uap:Extension Category="windows.protocol">
-          <uap:Protocol Name="ms-contact-profile">
-            <uap:DisplayName>Signal Private Messenger Contact</uap:DisplayName>
+          <uap:Protocol Name="ms-ipmessaging">
+            <uap:DisplayName>Signal Private Messenger Message</uap:DisplayName>
           </uap:Protocol>
         </uap:Extension>
         <uap:Extension Category="windows.protocol">
-          <uap:Protocol Name="ms-ipmessaging">
-            <uap:DisplayName>Signal Private Messenger Message</uap:DisplayName>
+          <uap:Protocol Name="ms-contact-profile">
+            <uap:DisplayName>Signal Private Messenger Contact</uap:DisplayName>
           </uap:Protocol>
         </uap:Extension>
+        <Extension Category="windows.backgroundTasks" EntryPoint="Signal_Windows.RC.SignalBackgroundTask">
+          <BackgroundTasks>
+            <Task Type="systemEvent" />
+            <Task Type="timer" />
+          </BackgroundTasks>
+        </Extension>
       </Extensions>
     </Application>
   </Applications>

Signal-Windows/ViewModels/FinishRegistrationPageViewModel.cs

@@ -1,4 +1,4 @@
-using System;
+using System;
 using System.Collections.Generic;
 using System.Diagnostics;
 using System.Linq;

Signal-Windows/ViewModels/LinkPageViewModel.cs

@@ -114,6 +114,7 @@ public async Task BeginLinking()
                     {
                         UIEnabled = false;
                         App.Store = store;
+                        SignalLibHandle.Instance.Store = store;
                     }).AsTask().Wait();
 
                     /* create prekeys */