To reproduce:
1. Launch Unity from terminal with -cleanedLogFile -quit -batchmode arguments

Actual: Crash
Expected: Unity shouldn't crash

Reproducible: 5.6.0b1, 5.5.0p1, 5.4.3p3, 5.3.7f1
Reproduced on OSX and Windows7

Stack trace:

Obtained 37 stack frames.
#0 0x007fff8f4a06c0 in flockfile
#1 0x007fff8f4a938d in vfprintf
#2 0x00000101334c0e in DefaultCleanLogHandlerv(LogType, char const*, __va_list_tag*)
#3 0x00000101335ea9 in CleanLogHandler(LogType, char const*, ...)
#4 0x00000101336301 in DebugStringToFilePostprocessedStacktrace(DebugStringToFileData const&)
#5 0x00000101336bb5 in DebugStringToFile(DebugStringToFileData const&)
#6 0x00000101334bbd in DebugStringToFile(char const*, int, char const*, int, int, int, int, void (*)(CppLogEntry const&))
#7 0x00000101476227 in AssetDatabase::RepairAssetTimestampCount()
#8 0x00000101476107 in AssetDatabase::RepairAssetDatabaseIfNeeded()
#9 0x000001014cf9fb in AssetInterface::PerformAssetDatabaseConsistencyChecks(bool)
#10 0x000001014d6a7a in AssetInterface::LoadAssetDatabase(bool, bool)
#11 0x000001014d4635 in AssetInterface::Initialize(bool, bool, int*)
#12 0x00000101a7a160 in Application::InitializeProject()
#13 0x00000101d68e76 in -[EditorApplication applicationDidFinishLaunching:]
#14 0x007fff7a40463c in __CFNOTIFICATIONCENTER_IS_CALLING_OUT_TO_AN_OBSERVER__
#15 0x007fff7a40453b in _CFXRegistrationPost
#16 0x007fff7a4042a2 in ___CFXNotificationPost_block_invoke
#17 0x007fff7a3c19a3 in -[_CFXNotificationRegistrar find:object:observer:enumerator:]
#18 0x007fff7a3c09dc in _CFXNotificationPost
#19 0x007fff7bdd00e3 in -[NSNotificationCenter postNotificationName:object:userInfo:]
#20 0x007fff781c77e5 in -[NSApplication _postDidFinishNotification]
#21 0x007fff781c754a in -[NSApplication _sendFinishLaunchingNotification]
#22 0x007fff7808b4e3 in -[NSApplication(NSAppleEventHandling) _handleAEOpenEvent:]
#23 0x007fff7808b138 in -[NSApplication(NSAppleEventHandling) _handleCoreEvent:withReplyEvent:]
#24 0x007fff7be1b55d in -[NSAppleEventManager dispatchRawAppleEvent:withRawReply:handlerRefCon:]
#25 0x007fff7be1b3d7 in _NSAppleEventManagerGenericHandler
#26 0x007fff7b22346a in aeDispatchAppleEvent(AEDesc const*, AEDesc*, unsigned int, unsigned char*)
#27 0x007fff7b2231e1 in dispatchEventAndSendReply(AEDesc const*, AEDesc*)
#28 0x007fff7b2230ed in aeProcessAppleEvent
#29 0x007fff799a069f in AEProcessAppleEvent
#30 0x007fff780868c3 in _DPSNextEvent
#31 0x007fff787968eb in -[NSApplication(NSEvent) _nextEventMatchingEventMask:untilDate:inMode:dequeue:]
#32 0x007fff7807afbd in -[NSApplication run]
#33 0x007fff78045a8a in NSApplicationMain
#34 0x00000101d7fb89 in EditorMain(int, char const**)
#35 0x00000101d80249 in main
#36 0x00000100002064 in start