diff --git a/Riot/Modules/Contacts/DataSources/ContactsDataSource.m b/Riot/Modules/Contacts/DataSources/ContactsDataSource.m
index 52a68f130..d52a46b1a 100644
--- a/Riot/Modules/Contacts/DataSources/ContactsDataSource.m
+++ b/Riot/Modules/Contacts/DataSources/ContactsDataSource.m
@@ -196,21 +196,25 @@
                 [hsUserDirectoryOperation cancel];
                 hsUserDirectoryOperation = nil;
             }
+            
+            MXWeakify(self);
 
             hsUserDirectoryOperation = [self.mxSession.matrixRestClient searchUsers:searchText limit:50 success:^(MXUserSearchResponse *userSearchResponse) {
-
-                filteredMatrixContacts = [NSMutableArray arrayWithCapacity:userSearchResponse.results.count];
+                
+                MXStrongifyAndReturnIfNil(self);
+                
+                self->filteredMatrixContacts = [NSMutableArray arrayWithCapacity:userSearchResponse.results.count];
 
                 // Keep the response order as the hs ordered users by relevance
                 for (MXUser *mxUser in userSearchResponse.results)
                 {
                     MXKContact *contact = [[MXKContact alloc] initMatrixContactWithDisplayName:mxUser.displayname andMatrixID:mxUser.userId];
-                    [filteredMatrixContacts addObject:contact];
+                    [self->filteredMatrixContacts addObject:contact];
                 }
 
-                hsUserDirectoryOperation = nil;
+                self->hsUserDirectoryOperation = nil;
 
-                _userDirectoryState = userSearchResponse.limited ? ContactsDataSourceUserDirectoryStateLoadedButLimited : ContactsDataSourceUserDirectoryStateLoaded;
+                self->_userDirectoryState = userSearchResponse.limited ? ContactsDataSourceUserDirectoryStateLoadedButLimited : ContactsDataSourceUserDirectoryStateLoaded;
 
                 // And inform the delegate about the update
                 [self.delegate dataSource:self didCellChange:nil];
@@ -230,28 +234,32 @@
         // Disclose the sections
         shrinkedSectionsBitMask = 0;
     }
+    
+    MXWeakify(self);
 
     dispatch_async(searchProcessingQueue, ^{
         
+        MXStrongifyAndReturnIfNil(self);
+        
         // Reset the current arrays if it is required
         if (!searchText.length)
         {
-            searchProcessingLocalContacts = nil;
-            searchProcessingMatrixContacts = nil;
+            self->searchProcessingLocalContacts = nil;
+            self->searchProcessingMatrixContacts = nil;
         }
         else if (unfilteredLocalContacts)
         {
-            searchProcessingLocalContacts = unfilteredLocalContacts;
-            searchProcessingMatrixContacts = unfilteredMatrixContacts;
+            self->searchProcessingLocalContacts = unfilteredLocalContacts;
+            self->searchProcessingMatrixContacts = unfilteredMatrixContacts;
         }
         
-        for (NSUInteger index = 0; index < searchProcessingLocalContacts.count;)
+        for (NSUInteger index = 0; index < self->searchProcessingLocalContacts.count;)
         {
-            MXKContact* contact = searchProcessingLocalContacts[index];
+            MXKContact* contact = self->searchProcessingLocalContacts[index];
             
             if (![contact hasPrefix:searchText])
             {
-                [searchProcessingLocalContacts removeObjectAtIndex:index];
+                [self->searchProcessingLocalContacts removeObjectAtIndex:index];
             }
             else
             {
@@ -260,13 +268,13 @@
             }
         }
         
-        for (NSUInteger index = 0; index < searchProcessingMatrixContacts.count;)
+        for (NSUInteger index = 0; index < self->searchProcessingMatrixContacts.count;)
         {
-            MXKContact* contact = searchProcessingMatrixContacts[index];
+            MXKContact* contact = self->searchProcessingMatrixContacts[index];
             
             if (![contact hasPrefix:searchText])
             {
-                [searchProcessingMatrixContacts removeObjectAtIndex:index];
+                [self->searchProcessingMatrixContacts removeObjectAtIndex:index];
             }
             else
             {
@@ -276,42 +284,41 @@
         }
         
         // Sort the refreshed list of the invitable contacts
-        [[MXKContactManager sharedManager] sortAlphabeticallyContacts:searchProcessingLocalContacts];
-        [[MXKContactManager sharedManager] sortContactsByLastActiveInformation:searchProcessingMatrixContacts];
+        [[MXKContactManager sharedManager] sortAlphabeticallyContacts:self->searchProcessingLocalContacts];
+        [[MXKContactManager sharedManager] sortContactsByLastActiveInformation:self->searchProcessingMatrixContacts];
         
-        searchProcessingText = searchText;
+        self->searchProcessingText = searchText;
+        
+        MXWeakify(self);
         
         dispatch_sync(dispatch_get_main_queue(), ^{
             
             // Sanity check: check whether self has been destroyed.
-            if (!searchProcessingQueue)
-            {
-                return;
-            }
+            MXStrongifyAndReturnIfNil(self);
             
             // Render the search result only if there is no other search in progress.
-            searchProcessingCount --;
+            self->searchProcessingCount --;
             
-            if (!searchProcessingCount)
+            if (!self->searchProcessingCount)
             {
-                if (!forceSearchResultRefresh)
+                if (!self->forceSearchResultRefresh)
                 {
                     // Update the filtered contacts.
-                    currentSearchText = searchProcessingText;
-                    filteredLocalContacts = searchProcessingLocalContacts;
+                    self->currentSearchText = self->searchProcessingText;
+                    self->filteredLocalContacts = self->searchProcessingLocalContacts;
 
                     if (!hsUserDirectory)
                     {
-                        filteredMatrixContacts = searchProcessingMatrixContacts;
-                        _userDirectoryState = ContactsDataSourceUserDirectoryStateOfflineLoaded;
+                        self->filteredMatrixContacts = self->searchProcessingMatrixContacts;
+                        self->_userDirectoryState = ContactsDataSourceUserDirectoryStateOfflineLoaded;
                     }
                     
                     if (!self.forceMatrixIdInDisplayName)
                     {
-                        [isMultiUseNameByDisplayName removeAllObjects];
-                        for (MXKContact* contact in filteredMatrixContacts)
+                        [self->isMultiUseNameByDisplayName removeAllObjects];
+                        for (MXKContact* contact in self->filteredMatrixContacts)
                         {
-                            isMultiUseNameByDisplayName[contact.displayName] = (isMultiUseNameByDisplayName[contact.displayName] ? @(YES) : @(NO));
+                            self->isMultiUseNameByDisplayName[contact.displayName] = (self->isMultiUseNameByDisplayName[contact.displayName] ? @(YES) : @(NO));
                         }
                     }
                     
@@ -321,8 +328,8 @@
                 else
                 {
                     // Launch a new search
-                    forceSearchResultRefresh = NO;
-                    [self searchWithPattern:searchProcessingText forceReset:YES];
+                    self->forceSearchResultRefresh = NO;
+                    [self searchWithPattern:self->searchProcessingText forceReset:YES];
                 }
             }
         });
diff --git a/changelog.d/4677.misc b/changelog.d/4677.misc
new file mode 100644
index 000000000..69490e109
--- /dev/null
+++ b/changelog.d/4677.misc
@@ -0,0 +1 @@
+Contacts: Fix implicitly retained self warnings.