diff --git a/Signal/src/Models/AccountManager.swift b/Signal/src/Models/AccountManager.swift
index b3a1dd433..eda61a06c 100644
--- a/Signal/src/Models/AccountManager.swift
+++ b/Signal/src/Models/AccountManager.swift
@@ -19,8 +19,7 @@ public class AccountManager: NSObject {
     }
 
     @objc
-    public override init()
-    {
+    public override init() {
         super.init()
 
         SwiftSingletons.register(self)
@@ -72,7 +71,9 @@ public class AccountManager: NSObject {
             default:
                 throw error
             }
-        }.done {
+        }.then { (_) in
+            self.tsAccountManager.performUpdateAccountAttributes()
+        }.done { (_) in
             self.completeRegistration()
         }
 
diff --git a/SignalMessaging/contacts/OWSSyncManager.m b/SignalMessaging/contacts/OWSSyncManager.m
index bab197b47..6d05c22cf 100644
--- a/SignalMessaging/contacts/OWSSyncManager.m
+++ b/SignalMessaging/contacts/OWSSyncManager.m
@@ -226,6 +226,10 @@ NSString *const kSyncManagerLastContactSyncKey = @"kTSStorageManagerOWSSyncManag
 - (void)sendConfigurationSyncMessage_AppReady {
     DDLogInfo(@"");
 
+    if (![TSAccountManager sharedInstance].isRegistered) {
+        return;
+    }
+
     BOOL areReadReceiptsEnabled = SSKEnvironment.shared.readReceiptManager.areReadReceiptsEnabled;
     BOOL showUnidentifiedDeliveryIndicators = Environment.shared.preferences.shouldShowUnidentifiedDeliveryIndicators;
     BOOL showTypingIndicators = self.typingIndicators.areTypingIndicatorsEnabled;
diff --git a/SignalServiceKit/src/Account/TSAccountManager.h b/SignalServiceKit/src/Account/TSAccountManager.h
index 523cd4919..f2c3dd821 100644
--- a/SignalServiceKit/src/Account/TSAccountManager.h
+++ b/SignalServiceKit/src/Account/TSAccountManager.h
@@ -144,6 +144,9 @@ extern NSString *const kNSNotificationName_LocalNumberDidChange;
 
 - (AnyPromise *)updateAccountAttributes;
 
+// This should only be used during the registration process.
+- (AnyPromise *)performUpdateAccountAttributes;
+
 @end
 
 NS_ASSUME_NONNULL_END
diff --git a/SignalServiceKit/src/Account/TSAccountManager.m b/SignalServiceKit/src/Account/TSAccountManager.m
index 35586c0b6..ef5d9da2a 100644
--- a/SignalServiceKit/src/Account/TSAccountManager.m
+++ b/SignalServiceKit/src/Account/TSAccountManager.m
@@ -659,8 +659,7 @@ NSString *const TSAccountManager_NeedsAccountAttributesUpdateKey = @"TSAccountMa
     if (!updateRequestDate) {
         return [AnyPromise promiseWithValue:@(1)];
     }
-
-    AnyPromise *promise = [[SignalServiceRestClient new] updateAccountAttributesObjC];
+    AnyPromise *promise = [self performUpdateAccountAttributes];
     promise = promise.then(^(id value) {
         [self.dbConnection readWriteWithBlock:^(YapDatabaseReadWriteTransaction *transaction) {
             // Clear the update request unless a new update has been requested
@@ -673,7 +672,14 @@ NSString *const TSAccountManager_NeedsAccountAttributesUpdateKey = @"TSAccountMa
                                    inCollection:TSAccountManager_UserAccountCollection];
             }
         }];
+    });
+    return promise;
+}
 
+- (AnyPromise *)performUpdateAccountAttributes
+{
+    AnyPromise *promise = [[SignalServiceRestClient new] updateAccountAttributesObjC];
+    promise = promise.then(^(id value) {
         // Fetch the local profile, as we may have changed its
         // account attributes.  Specifically, we need to determine
         // if all devices for our account now support UD for sync
diff --git a/SignalServiceKit/src/Messages/OWSMessageSender.m b/SignalServiceKit/src/Messages/OWSMessageSender.m
index e327b7f0b..3cf3d7629 100644
--- a/SignalServiceKit/src/Messages/OWSMessageSender.m
+++ b/SignalServiceKit/src/Messages/OWSMessageSender.m
@@ -688,6 +688,18 @@ NSString *const OWSMessageSenderRateLimitedException = @"RateLimitedException";
 
     TSThread *_Nullable thread = message.thread;
 
+    BOOL isSyncMessage = [message isKindOfClass:[OWSOutgoingSyncMessage class]];
+    if (!thread && !isSyncMessage) {
+        OWSFailDebug(@"Missing thread for non-sync message.");
+
+        // This thread has been deleted since the message was enqueued.
+        NSError *error = OWSErrorWithCodeDescription(OWSErrorCodeMessageSendNoValidRecipients,
+            NSLocalizedString(@"ERROR_DESCRIPTION_NO_VALID_RECIPIENTS",
+                @"Error indicating that an outgoing message had no valid recipients."));
+        [error setIsRetryable:NO];
+        return failureHandler(error);
+    }
+
     // In the "self-send" special case, we ony need to send a sync message with a delivery receipt.
     if ([thread isKindOfClass:[TSContactThread class]] &&
         [((TSContactThread *)thread).contactIdentifier isEqualToString:[TSAccountManager localNumber]]) {