diff --git a/Signal/src/Jobs/ConversationConfigurationSyncOperation.swift b/Signal/src/Jobs/ConversationConfigurationSyncOperation.swift
index 79ef663a6..783c8af68 100644
--- a/Signal/src/Jobs/ConversationConfigurationSyncOperation.swift
+++ b/Signal/src/Jobs/ConversationConfigurationSyncOperation.swift
@@ -56,7 +56,7 @@ class ConversationConfigurationSyncOperation: OWSOperation {
             return
         }
 
-        syncManager.syncContacts(for: [signalAccount])
+        syncManager.syncContacts(for: [signalAccount]).retainUntilComplete()
     }
 
     private func sync(groupThread: TSGroupThread) {
diff --git a/Signal/src/ViewControllers/DebugUI/DebugUISyncMessages.m b/Signal/src/ViewControllers/DebugUI/DebugUISyncMessages.m
index bb0baad3c..b7ef29180 100644
--- a/Signal/src/ViewControllers/DebugUI/DebugUISyncMessages.m
+++ b/Signal/src/ViewControllers/DebugUI/DebugUISyncMessages.m
@@ -8,6 +8,7 @@
 #import "Signal-Swift.h"
 #import "ThreadUtil.h"
 #import <AxolotlKit/PreKeyBundle.h>
+#import <PromiseKit/AnyPromise.h>
 #import <SignalCoreKit/Randomness.h>
 #import <SignalMessaging/Environment.h>
 #import <SignalServiceKit/OWSBatchMessageProcessor.h>
@@ -102,7 +103,7 @@ NS_ASSUME_NONNULL_BEGIN
 
 + (void)sendContactsSyncMessage
 {
-    [self.syncManager syncAllContacts];
+    [[self.syncManager syncAllContacts] retainUntilComplete];
 }
 
 + (void)sendGroupSyncMessage
diff --git a/Signal/src/util/Backup/OWSBackup.h b/Signal/src/util/Backup/OWSBackup.h
index 20a2246be..4ad58c34e 100644
--- a/Signal/src/util/Backup/OWSBackup.h
+++ b/Signal/src/util/Backup/OWSBackup.h
@@ -77,7 +77,7 @@ NSError *OWSBackupErrorWithDescription(NSString *description);
 
 - (void)allRecipientIdsWithManifestsInCloud:(OWSBackupStringListBlock)success failure:(OWSBackupErrorBlock)failure;
 
-- (AnyPromise *)ensureCloudKitAccess;
+- (AnyPromise *)ensureCloudKitAccess __attribute__((warn_unused_result));
 
 - (void)checkCanImportBackup:(OWSBackupBoolBlock)success failure:(OWSBackupErrorBlock)failure;
 
@@ -98,7 +98,7 @@ NSError *OWSBackupErrorWithDescription(NSString *description);
 
 - (NSArray<NSString *> *)attachmentIdsForLazyRestore;
 
-- (AnyPromise *)lazyRestoreAttachment:(TSAttachmentPointer *)attachment backupIO:(OWSBackupIO *)backupIO;
+- (AnyPromise *)lazyRestoreAttachment:(TSAttachmentPointer *)attachment backupIO:(OWSBackupIO *)backupIO __attribute__((warn_unused_result));
 
 @end
 
diff --git a/Signal/src/util/Backup/OWSBackupJob.h b/Signal/src/util/Backup/OWSBackupJob.h
index 1c7c61f73..f82ce0ccf 100644
--- a/Signal/src/util/Backup/OWSBackupJob.h
+++ b/Signal/src/util/Backup/OWSBackupJob.h
@@ -85,7 +85,7 @@ typedef void (^OWSBackupJobManifestFailure)(NSError *error);
 
 #pragma mark - Manifest
 
-- (AnyPromise *)downloadAndProcessManifestWithBackupIO:(OWSBackupIO *)backupIO;
+- (AnyPromise *)downloadAndProcessManifestWithBackupIO:(OWSBackupIO *)backupIO __attribute__((warn_unused_result));
 
 @end
 
diff --git a/SignalMessaging/profiles/OWSProfileManager.m b/SignalMessaging/profiles/OWSProfileManager.m
index 23432e735..445efd0db 100644
--- a/SignalMessaging/profiles/OWSProfileManager.m
+++ b/SignalMessaging/profiles/OWSProfileManager.m
@@ -244,7 +244,7 @@ typedef void (^ProfileManagerFailureBlock)(NSError *error);
         //
         // NOTE: We also inform the desktop in the failure case,
         //       since that _may have_ affected service state.
-        [self.syncManager syncLocalContact];
+        [[self.syncManager syncLocalContact] retainUntilComplete];
 
         dispatch_async(dispatch_get_main_queue(), ^{
             failureBlockParameter();
@@ -256,7 +256,7 @@ typedef void (^ProfileManagerFailureBlock)(NSError *error);
         // We use a "self-only" contact sync to indicate to desktop
         // that we've changed our profile and that it should do a
         // profile fetch for "self".
-        [self.syncManager syncLocalContact];
+        [[self.syncManager syncLocalContact] retainUntilComplete];
 
         dispatch_async(dispatch_get_main_queue(), ^{
             successBlockParameter();
diff --git a/SignalMessaging/profiles/OWSUserProfile.m b/SignalMessaging/profiles/OWSUserProfile.m
index 3a798481d..f1775a946 100644
--- a/SignalMessaging/profiles/OWSUserProfile.m
+++ b/SignalMessaging/profiles/OWSUserProfile.m
@@ -3,6 +3,7 @@
 //
 
 #import "OWSUserProfile.h"
+#import <PromiseKit/AnyPromise.h>
 #import <SignalCoreKit/Cryptography.h>
 #import <SignalCoreKit/NSData+OWS.h>
 #import <SignalCoreKit/NSString+SSK.h>
@@ -11,6 +12,7 @@
 #import <SignalServiceKit/OWSFileSystem.h>
 #import <SignalServiceKit/OWSPrimaryStorage.h>
 #import <SignalServiceKit/SSKEnvironment.h>
+#import <SignalServiceKit/SignalServiceKit-Swift.h>
 #import <SignalServiceKit/TSAccountManager.h>
 #import <YapDatabase/YapDatabaseConnection.h>
 #import <YapDatabase/YapDatabaseTransaction.h>
@@ -227,7 +229,7 @@ NSString *const kLocalProfileUniqueId = @"kLocalProfileUniqueId";
             // we have a registered account, syncing will fail (and there could not be any
             // linked device to sync to at this point anyway).
             if ([self.tsAccountManager isRegistered] && CurrentAppContext().isMainApp) {
-                [self.syncManager syncLocalContact];
+                [[self.syncManager syncLocalContact] retainUntilComplete];
             }
 
             [[NSNotificationCenter defaultCenter] postNotificationNameAsync:kNSNotificationName_LocalProfileDidChange
diff --git a/SignalServiceKit/src/Account/TSAccountManager.h b/SignalServiceKit/src/Account/TSAccountManager.h
index d6205a5b0..27dff48e5 100644
--- a/SignalServiceKit/src/Account/TSAccountManager.h
+++ b/SignalServiceKit/src/Account/TSAccountManager.h
@@ -148,16 +148,16 @@ typedef NS_ENUM(NSUInteger, OWSRegistrationState) {
 #pragma mark - Manual Message Fetch
 
 - (BOOL)isManualMessageFetchEnabled;
-- (AnyPromise *)setIsManualMessageFetchEnabled:(BOOL)value;
+- (AnyPromise *)setIsManualMessageFetchEnabled:(BOOL)value __attribute__((warn_unused_result));
 
 #ifdef DEBUG
 - (void)registerForTestsWithLocalNumber:(NSString *)localNumber;
 #endif
 
-- (AnyPromise *)updateAccountAttributes;
+- (AnyPromise *)updateAccountAttributes __attribute__((warn_unused_result));
 
 // This should only be used during the registration process.
-- (AnyPromise *)performUpdateAccountAttributes;
+- (AnyPromise *)performUpdateAccountAttributes __attribute__((warn_unused_result));
 
 @end
 
diff --git a/SignalServiceKit/src/Messages/OWSMessageManager.m b/SignalServiceKit/src/Messages/OWSMessageManager.m
index 59dd0c543..e8652d5d9 100644
--- a/SignalServiceKit/src/Messages/OWSMessageManager.m
+++ b/SignalServiceKit/src/Messages/OWSMessageManager.m
@@ -901,7 +901,7 @@ NS_ASSUME_NONNULL_BEGIN
             // In rare cases this means we won't respond to the sync request, but that's
             // acceptable.
             dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{
-                [self.syncManager syncAllContacts];
+                [[self.syncManager syncAllContacts] retainUntilComplete];
             });
         } else if (syncMessage.request.type == SSKProtoSyncMessageRequestTypeGroups) {
             OWSSyncGroupsMessage *syncGroupsMessage = [[OWSSyncGroupsMessage alloc] init];
diff --git a/SignalServiceKit/src/Util/OWSSyncManagerProtocol.h b/SignalServiceKit/src/Util/OWSSyncManagerProtocol.h
index e4e3fa090..da5e28684 100644
--- a/SignalServiceKit/src/Util/OWSSyncManagerProtocol.h
+++ b/SignalServiceKit/src/Util/OWSSyncManagerProtocol.h
@@ -11,11 +11,11 @@ NS_ASSUME_NONNULL_BEGIN
 
 - (void)sendConfigurationSyncMessage;
 
-- (AnyPromise *)syncLocalContact;
+- (AnyPromise *)syncLocalContact __attribute__((warn_unused_result));
 
-- (AnyPromise *)syncAllContacts;
+- (AnyPromise *)syncAllContacts __attribute__((warn_unused_result));
 
-- (AnyPromise *)syncContactsForSignalAccounts:(NSArray<SignalAccount *> *)signalAccounts;
+- (AnyPromise *)syncContactsForSignalAccounts:(NSArray<SignalAccount *> *)signalAccounts __attribute__((warn_unused_result));
 
 @end