@eskimo Here is makeSetter, but I actually fixed the issue, for now? (explanation below the code) template<typename ArgType, typename StorageType=ArgType> id makeSetter(__unsafe_unretained RLMProperty *const prop) {     NSUInteger index = prop.index;     NSString *name = prop.name;     if (prop.isPrimary) {         return ^(__unused RLMObjectBase *obj, __unused ArgType val) {             @throw RLMException(@"Primary key can't be changed after an object is inserted.");         };     }     return ^(__unsafe_unretained RLMObjectBase *const obj, ArgType val) {         RLMVerifyInWriteTransaction(obj);         RLMObservationTracker tracker(obj->_realm);         tracker.willChange(RLMGetObservationInfo(obj->_observationInfo, obj->_row.get_key(), *obj->_info), name);         if constexpr (std::is_same_v<ArgType, RLMObjectBase *>) {             tracker.trackDeletions();         }         setValue(obj, get_property(obj, index).column_key, static_cast<StorageType>(val));     }; } So I actually fixed the issue and have App approved tonight. I had ATTrackingManager.requestTrackingAuthorization in App Delegate which appears to not be a place where you need to use it so I moved it to first viewcontroller. I uploaded it to App review and it got approved. I actually not sure if this was the problem as I told in original post previous version of the app had same code and was approved with working ATTrackingManager.requestTrackingAuthorization in App Delegate (and this function perfectly worked as well). I had no crashes anywhere as well so not sure if this me being lucky this time or ATTrackingManager.requestTrackingAuthorization can cause some deadblock or thread clash randomly with Realm. Maybe you have some insight on why that might happen so people with same problem can find the answer here? Anyway, thank you very much for your help I am very much appreciate it! Please have a wonderful day!

@eskimo Thank you very much! Here is what I have now: Last Exception Backtrace: 0 CoreFoundation 0x1aaf29288 __exceptionPreprocess + 220 1 libobjc.A.dylib 0x1c3c23744 objc_exception_throw + 60 2 Realm (anonymous namespace)::managedSetter(RLMProperty*, char const*) (in Realm) (RLMAccessor.mm:383) 3 Realm +[RLMObjectSchema schemaForObjectClass:] (in Realm) (RLMObjectSchema.mm:140) 4 RealmSwift Realm.add(_:update:) (in RealmSwift) (Realm.swift:438) 5 AppName one-time initialization function for pictureObjectIDandWordArray (in AppName) (TestWords.swift:179) 6 AppName specialized TopVideoCard.isChosen.willset (in AppName) (TopVideoCard.swift:91) 7 AppName one-time initialization function for testCategories2 (in AppName) (TestWords.swift:344) 8 RealmSwift Realm.write<A>(withoutNotifying:_:) (in RealmSwift) (Realm.swift:255) 9 AppName one-time initialization function for pictureObjectIDandWordArray (in AppName) (<compiler-generated>:0) 10 AppName AppDelegate.application(_:didFinishLaunchingWithOptions:) (in AppName) (AppDelegate.swift:257) 11 AppName AppDelegate.application(_:didFinishLaunchingWithOptions:) (in AppName) (<compiler-generated>:0) 12 UIKitCore 0x1ad62f72c -[UIApplication _handleDelegateCallbacksWithOptions:isSuspended:restoreState:] + 340 13 UIKitCore 0x1ad816564 -[UIApplication _callInitializationDelegatesWithActions:forCanvas:payload:fromOriginatingProcess:] + 3572 14 UIKitCore 0x1ad7ff118 -[UIApplication _runWithMainScene:transitionContext:completion:] + 1180 15 UIKitCore 0x1ad65cd34 -[_UISceneLifecycleMultiplexer completeApplicationLaunchWithFBSScene:transitionContext:] + 152 16 UIKitCore 0x1ad4b73b4 _UIScenePerformActionsWithLifecycleActionMask + 104 17 UIKitCore 0x1ad5e1d90 __101-[_UISceneLifecycleMultiplexer Here is parts of those files (with line number after //: RLMAccessor: id managedSetter(RLMProperty *prop, const char *type) { if (prop.array && prop.type != RLMPropertyTypeLinkingObjects) { return makeSetter<id<NSFastEnumeration>>(prop); } bool boxed = prop.optional || *type == '@'; switch (prop.type) { case RLMPropertyTypeInt: if (boxed) { return makeSetter<NSNumber<RLMInt> *>(prop); } switch (*type) { case 'c': return makeSetter<char, long long>(prop); case 's': return makeSetter<short, long long>(prop); case 'i': return makeSetter<int, long long>(prop); case 'l': return makeSetter<long, long long>(prop); case 'q': return makeSetter<long long>(prop); default: @throw RLMException(@"Unexpected property type for Objective-C type code"); } case RLMPropertyTypeFloat: return boxed ? makeSetter<NSNumber<RLMFloat> *>(prop) : makeSetter<float>(prop); // line 383 case RLMPropertyTypeDouble: return boxed ? makeSetter<NSNumber<RLMDouble> *>(prop) : makeSetter<double>(prop); case RLMPropertyTypeBool: return boxed ? makeSetter<NSNumber<RLMBool> *>(prop) : makeSetter<BOOL, bool>(prop); case RLMPropertyTypeString: return makeSetter<NSString *>(prop); case RLMPropertyTypeDate: return makeSetter<NSDate *>(prop); case RLMPropertyTypeData: return makeSetter<NSData *>(prop); case RLMPropertyTypeAny: return nil; case RLMPropertyTypeLinkingObjects: return nil; case RLMPropertyTypeObject: return makeSetter<RLMObjectBase *>(prop); case RLMPropertyTypeObjectId: return makeSetter<RLMObjectId *>(prop); case RLMPropertyTypeDecimal128: return makeSetter<RLMDecimal128 *>(prop); } } RLMObjectSchema: if (allProperties.count != [NSSet setWithArray:[allProperties valueForKey:@"name"]].count) { NSCountedSet *countedPropertyNames = [NSCountedSet setWithArray:[allProperties valueForKey:@"name"]]; NSArray *duplicatePropertyNames = [countedPropertyNames filteredSetUsingPredicate:[NSPredicate predicateWithBlock:^BOOL(id object, NSDictionary *) { // line 140 return [countedPropertyNames countForObject:object] > 1; }]].allObjects; if (duplicatePropertyNames.count == 1) { @throw RLMException(@"Property '%@' is declared multiple times in the class hierarchy of '%@'", duplicatePropertyNames.firstObject, className); } else { @throw RLMException(@"Object '%@' has properties that are declared multiple times in its class hierarchy: '%@'", className, [duplicatePropertyNames componentsJoinedByString:@"', '"]); } } Realm.swift public func add(_ object: Object, update: UpdatePolicy = .error) {         if update != .error && object.objectSchema.primaryKeyProperty == nil {             throwRealmException("'\(object.objectSchema.className)' does not have a primary key and can not be updated")         }         // remove any observers still attached to the Realm.         // if not using SwiftUI, this is a noop         if #available(iOS 13.0, macOS 10.15, tvOS 13.0, watchOS 6.0, *) {             SwiftUIKVO.removeObservers(object: object)         }         RLMAddObjectToRealm(object, rlmRealm, RLMUpdatePolicy(rawValue: UInt(update.rawValue))!)     } // line 438 Thank you very much for your help!

@eskimo Hello, thank you very much for your answer. Looks like Facebook SDK(?) crashing the app? I’m not sure how you came to that conclusion. Don’t mistake the FB in FBSScene for Facebook. That stands for FrontBoardServices, which is a system library that’s involved in app lifecycle management. Yeah I already understood regarding FrontBoardServices, the last thing that I have added to my code was Facebook SDK thats why it got me thinking that FB stands for Facebook yes, sorry about that:) If you have Realm source code you should symbolicate frame 2 to get a file and line number and then see what that’s complaining about. For details on how to do this, see Adding Identifiable Symbol Names to a Crash Report. If you don’t have Realm source code, you should ask the Realm folks about this. I have Realm source code but I am not sure how to proceed further. I have symbolicated crash reports I got from App Review as per "Symbolicate the Crash Report in Xcode" in your link and this is what I have included in initial post. Not sure what should I do further here?

@andrefreitas Hi, thank you very much for your answer. i see in the crash log that device is now the iPhone, so probably things changed. But just to make sure I ran on iPad now with same result - all works fine. I don't have user account in the app so no restrictions like this The problem is that the build of the app that is currently live on App Store (which was approved) is same as this one that crashes - and it works fine. The only thing that changed between builds is two strings with version number and as far as I know nothing relies on those strings. Looks like Realm is crashing on launch (I have database creation on first run) and probably review configuration is different from TestFlight/XCode/App Store version?

Same here beta 6

I have same problem (still have it in TestFlight) - suddenly without any changes in code I started to get "Code=4994 "The requested application data doesn’t exist."" error. All tags are same. Hovewer it worked in xcode. After month or so I came back to this problem (the app is not in the store yet) and now even xcode is not working and I always get this error. Not sure what to do now as self hosting is too much effort for now, hope this will be fixed soon.