People at Apple apparently are not capable of writing stable code. After Big Sur update I started getting this 0   CoreFoundation            0x00007fff204976af __exceptionPreprocess + 242 1   libobjc.A.dylib            0x00007fff201cf3c9 objc_exception_throw + 48 2   CoreFoundation            0x00007fff204c0512 +[NSException raise:format:arguments:] + 88 3   Foundation              0x00007fff212796c9 -[NSAssertionHandler handleFailureInMethod:object:file:lineNumber:description:] + 191 4   AccountsDaemon            0x00007fff37dd111e -[ACDDatabaseConnection _persistentStore] + 258 5   AccountsDaemon            0x00007fff37dd0f20 -[ACDDatabaseConnection version] + 28 6   AccountsDaemon            0x00007fff37d89c1c __58-[ACDDatabaseInitializer updateDefaultContentIfNecessary:]_block_invoke + 60 7   CoreData               0x00007fff25ad2821 developerSubmittedBlockToNSManagedObjectContextPerform + 161 Does anybody know what is ACDDatabase, where to find it and how to fix this. Cause I am completely locked out of my Mac account now and apple support is useless. Error is Exception Type:     EXC_CRASH (SIGABRT) Exception Codes:     0x0000000000000000, 0x0000000000000000 Exception Note:     EXC_CORPSE_NOTIFY Application Specific Information: Event history: (    "Error Domain=NSCocoaErrorDomain Code=134100 \"The managed object model version used to open the persistent store is incompatible with the one that was used to create the persistent store.\" UserInfo={metadata={\n   ACAccountTypeVersion = 94;\n   NSPersistenceFrameworkVersion = 977;\n   NSStoreModelVersionHashes =    {\n     AccessOptionsKey = {length = 32, bytes = ... };\n     Account = {length = 32, bytes = ... };\n     AccountProperty = {length = 32, bytes = ... };\n     AccountType = {length = 32, bytes =... ... .....};\n     Authorization = {length = 32, bytes = ... };\n     CredentialItem = {length = 32, bytes = ... };\n     Dataclass = {length = 32, bytes = ...n   NSStoreModelVersionHashesVersion = 3;\n   NSStoreModelVersionIdentifiers =    (\n     25\n   );\n   NSStoreType = SQLite;\n   NSStoreUUID = \"BAEEF0BE-...\";\n   \"_NSAutoVacuumLevel\" = 2;\n}, reason=The model used to open the store is incompatible with the one used to create the store}" )** Terminating app due to uncaught exception 'NSInternalInconsistencyException', reason: 'Unexpected number of persistent stores (0), expected 1' abort() called terminating with uncaught exception of type NSException