diff --git a/Signal/src/ViewControllers/CallViewController.swift b/Signal/src/ViewControllers/CallViewController.swift
index f5541c3fe..ab10eb0cd 100644
--- a/Signal/src/ViewControllers/CallViewController.swift
+++ b/Signal/src/ViewControllers/CallViewController.swift
@@ -25,6 +25,7 @@ class CallViewController: OWSViewController, CallObserver, CallServiceObserver,
 
     // MARK: Views
 
+    var isViewLoaded = false
     var hasConstraints = false
     var blurView: UIVisualEffectView!
     var dateFormatter: DateFormatter?
@@ -158,7 +159,9 @@ class CallViewController: OWSViewController, CallObserver, CallServiceObserver,
     }
 
     func didBecomeActive() {
-        shouldRemoteVideoControlsBeHidden = false
+        if (self.isViewLoaded) {
+            shouldRemoteVideoControlsBeHidden = false
+        }
     }
 
     // MARK: View Lifecycle
@@ -195,6 +198,7 @@ class CallViewController: OWSViewController, CallObserver, CallServiceObserver,
         call.addObserverAndSyncState(observer: self)
 
         Environment.getCurrent().callService.addObserverAndSyncState(observer: self)
+        self.isViewLoaded = true
     }
 
     // MARK: - Create Views
diff --git a/Signal/src/ViewControllers/ConversationView/MessagesViewController.m b/Signal/src/ViewControllers/ConversationView/MessagesViewController.m
index 2c97a138c..2dd5a2faa 100644
--- a/Signal/src/ViewControllers/ConversationView/MessagesViewController.m
+++ b/Signal/src/ViewControllers/ConversationView/MessagesViewController.m
@@ -487,8 +487,17 @@ typedef NS_ENUM(NSInteger, MessagesRangeSizeMode) {
     _callOnOpen = callOnViewAppearing;
 
     [self.uiDatabaseConnection beginLongLivedReadTransaction];
-    self.messageMappings =
-        [[YapDatabaseViewMappings alloc] initWithGroups:@[ thread.uniqueId ] view:TSMessageDatabaseViewExtensionName];
+
+    if (thread.uniqueId.length > 0) {
+        self.messageMappings = [[YapDatabaseViewMappings alloc] initWithGroups:@[ thread.uniqueId ]
+                                                                          view:TSMessageDatabaseViewExtensionName];
+    } else {
+        OWSFail(@"uniqueId unexpectedly empty for thread: %@", thread);
+        self.messageMappings =
+            [[YapDatabaseViewMappings alloc] initWithGroups:@[] view:TSMessageDatabaseViewExtensionName];
+        return;
+    }
+
     // We need to impose the range restrictions on the mappings immediately to avoid
     // doing a great deal of unnecessary work and causing a perf hotspot.
     [self.uiDatabaseConnection readWithBlock:^(YapDatabaseReadTransaction *transaction) {
@@ -2202,33 +2211,38 @@ typedef NS_ENUM(NSInteger, MessagesRangeSizeMode) {
                 if ([[messageItem media] isKindOfClass:[TSPhotoAdapter class]]) {
                     TSPhotoAdapter *messageMedia = (TSPhotoAdapter *)[messageItem media];
 
-                    UIImage *tappedImage = ((UIImageView *)[messageMedia mediaView]).image;
+                    UIView *mediaView = [messageMedia mediaView];
+                    if (![mediaView isKindOfClass:[UIImageView class]]) {
+                        OWSFail(@"unexpected mediaView of type: %@", [mediaView class]);
+                        return;
+                    }
+                    UIImageView *imageView = (UIImageView *)mediaView;
+                    UIImage *tappedImage = imageView.image;
                     if (tappedImage == nil) {
                         DDLogWarn(@"tapped TSPhotoAdapter with nil image");
-                    } else {
-                        UIWindow *window = [UIApplication sharedApplication].keyWindow;
-                        JSQMessagesCollectionViewCell *cell
-                            = (JSQMessagesCollectionViewCell *)[collectionView cellForItemAtIndexPath:indexPath];
-                        OWSAssert([cell isKindOfClass:[JSQMessagesCollectionViewCell class]]);
-                        CGRect convertedRect = [cell.mediaView convertRect:cell.mediaView.bounds toView:window];
+                        return;
+                    }
+                    UIWindow *window = [UIApplication sharedApplication].keyWindow;
+                    JSQMessagesCollectionViewCell *cell
+                        = (JSQMessagesCollectionViewCell *)[collectionView cellForItemAtIndexPath:indexPath];
+                    OWSAssert([cell isKindOfClass:[JSQMessagesCollectionViewCell class]]);
+                    CGRect convertedRect = [cell.mediaView convertRect:cell.mediaView.bounds toView:window];
 
-                        __block TSAttachment *attachment = nil;
-                        [self.uiDatabaseConnection readWithBlock:^(YapDatabaseReadTransaction *transaction) {
-                            attachment = [TSAttachment fetchObjectWithUniqueID:messageMedia.attachmentId
-                                                                   transaction:transaction];
-                        }];
+                    __block TSAttachment *attachment = nil;
+                    [self.uiDatabaseConnection readWithBlock:^(YapDatabaseReadTransaction *transaction) {
+                        attachment =
+                            [TSAttachment fetchObjectWithUniqueID:messageMedia.attachmentId transaction:transaction];
+                    }];
 
-                        if ([attachment isKindOfClass:[TSAttachmentStream class]]) {
-                            TSAttachmentStream *attStream = (TSAttachmentStream *)attachment;
-                            FullImageViewController *vc =
-                                [[FullImageViewController alloc] initWithAttachment:attStream
-                                                                           fromRect:convertedRect
-                                                                     forInteraction:interaction
-                                                                        messageItem:messageItem
-                                                                         isAnimated:NO];
+                    if ([attachment isKindOfClass:[TSAttachmentStream class]]) {
+                        TSAttachmentStream *attStream = (TSAttachmentStream *)attachment;
+                        FullImageViewController *vc = [[FullImageViewController alloc] initWithAttachment:attStream
+                                                                                                 fromRect:convertedRect
+                                                                                           forInteraction:interaction
+                                                                                              messageItem:messageItem
+                                                                                               isAnimated:NO];
 
-                            [vc presentFromViewController:self];
-                        }
+                        [vc presentFromViewController:self];
                     }
                 } else if ([[messageItem media] isKindOfClass:[TSAnimatedAdapter class]]) {
                     // Show animated image full-screen
@@ -3956,20 +3970,30 @@ typedef NS_ENUM(NSInteger, MessagesRangeSizeMode) {
 
     TSThread *thread = self.thread;
     uint64_t lastVisibleTimestamp = self.lastVisibleTimestamp;
+
     [self.editingDatabaseConnection asyncReadWriteWithBlock:^(YapDatabaseReadWriteTransaction *_Nonnull transaction) {
         NSMutableArray<id<OWSReadTracking>> *interactions = [NSMutableArray new];
+        
         [[TSDatabaseView unseenDatabaseViewExtension:transaction]
             enumerateRowsInGroup:thread.uniqueId
                       usingBlock:^(
                           NSString *collection, NSString *key, id object, id metadata, NSUInteger index, BOOL *stop) {
 
-                          TSInteraction *interaction = object;
-                          if (interaction.timestampForSorting > lastVisibleTimestamp) {
+                          if (![object conformsToProtocol:@protocol(OWSReadTracking)]) {
+                              OWSFail(@"Expected to conform to OWSReadTracking: object with class: %@ collection: %@ "
+                                      @"key: %@",
+                                  [object class],
+                                  collection,
+                                  key);
+                              return;
+                          }
+                          id<OWSReadTracking> possiblyRead = (id<OWSReadTracking>)object;
+
+                          if (possiblyRead.timestampForSorting > lastVisibleTimestamp) {
                               *stop = YES;
                               return;
                           }
 
-                          id<OWSReadTracking> possiblyRead = (id<OWSReadTracking>)object;
                           OWSAssert(!possiblyRead.read);
                           if (!possiblyRead.read) {
                               [interactions addObject:possiblyRead];
diff --git a/Signal/src/ViewControllers/SignalsViewController.m b/Signal/src/ViewControllers/SignalsViewController.m
index 86d63a7be..57f6be088 100644
--- a/Signal/src/ViewControllers/SignalsViewController.m
+++ b/Signal/src/ViewControllers/SignalsViewController.m
@@ -726,6 +726,11 @@ typedef NS_ENUM(NSInteger, CellState) { kArchiveState, kInboxState };
     keyboardOnViewAppearing:(BOOL)keyboardOnViewAppearing
         callOnViewAppearing:(BOOL)callOnViewAppearing
 {
+    if (thread == nil) {
+        OWSFail(@"Thread unexpectedly nil");
+        return;
+    }
+
     // We do this synchronously if we're already on the main thread.
     DispatchMainThreadSafe(^{
         MessagesViewController *mvc = [[MessagesViewController alloc] initWithNibName:@"MessagesViewController"
diff --git a/SignalServiceKit/src/Contacts/TSThread.m b/SignalServiceKit/src/Contacts/TSThread.m
index 8acc9eead..d53150622 100644
--- a/SignalServiceKit/src/Contacts/TSThread.m
+++ b/SignalServiceKit/src/Contacts/TSThread.m
@@ -221,7 +221,8 @@ NS_ASSUME_NONNULL_BEGIN
                       NSString *collection, NSString *key, id object, id metadata, NSUInteger index, BOOL *stop) {
 
                       if (![object conformsToProtocol:@protocol(OWSReadTracking)]) {
-                          DDLogError(@"%@ Unexpected object in unread messages: %@", self.tag, object);
+                          OWSFail(@"%@ Unexpected object in unread messages: %@", self.tag, object);
+                          return;
                       }
                       [messages addObject:(id<OWSReadTracking>)object];
                   }];
diff --git a/SignalServiceKit/src/Messages/OWSReadTracking.h b/SignalServiceKit/src/Messages/OWSReadTracking.h
index 5236753bb..ed3dd27be 100644
--- a/SignalServiceKit/src/Messages/OWSReadTracking.h
+++ b/SignalServiceKit/src/Messages/OWSReadTracking.h
@@ -15,6 +15,7 @@
  */
 @property (nonatomic, readonly, getter=wasRead) BOOL read;
 
+@property (nonatomic, readonly) uint64_t timestampForSorting;
 @property (nonatomic, readonly) NSString *uniqueThreadId;
 
 - (BOOL)shouldAffectUnreadCounts;