Error map
Unexpectedly found nil Fatal error: Unexpectedly found nil while unwrapping an Optional value
iOS · layer 1, On your device
Centre: this error. First ring: errors it is linked with (12). Outer ring: what those are linked with. Colours show the layer of a request each error belongs to. Click any dot to re-centre the map on it; hover to follow its connections. The centre dot opens the error page.
Directly related (12)
TypeError: Cannot read properties of undefined (reading 'x')
You tried to access a property on a value that is `undefined` (or `null`) — usually data that hasn’t loaded yet or a wrong proper…
java.lang.NullPointerException
Code called a method or accessed a field on a reference that is `null`.
Thread 1: signal SIGABRT (app crashes with "libc++abi: terminating")
The app deliberately aborted — an uncaught exception, failed assertion or fatalError. The console above the crash has the real me…
System.NullReferenceException: Object reference not set to an instance of an object
Code dereferenced a variable that is `null` — the .NET equivalent of Java’s NullPointerException.
The application was unable to start correctly (0xc0000142)
A DLL the program loads failed to initialise — often after an update, with corrupt runtimes, or when a desktop heap/session limit…
C++: terminate called after throwing an instance of 'std::out_of_range' — what(): vector::_M_range_check
A C++ exception wasn’t caught anywhere, so std::terminate aborted the program. what() tells you the reason.
dyld: Library not loaded: @rpath/X.framework/X — Reason: image not found (crash on launch)
A dynamic framework the app needs at runtime isn’t embedded in the app bundle, so it crashes at launch.
java.util.NoSuchElementException: No value present
Code asked for an element that doesn’t exist — Optional.get() on empty, iterator.next() past the end, Scanner with no input.
Illegal instruction (core dumped) (SIGILL)
The program used a CPU instruction your processor doesn’t support — typically AVX/AVX2 in prebuilt binaries (TensorFlow, MongoDB…
C/C++: free(): double free detected / double free or corruption (out) — Aborted (core dumped)
Memory was freed twice or the heap was corrupted (buffer overflow, freeing a non-heap pointer), so glibc aborted the program.
The application was unable to start correctly (0xc0000005) / Exception code 0xc0000005 access violation
A program tried to read or write memory it doesn’t own and Windows stopped it — buggy software, bad drivers/plugins, security sof…
SwiftUI Preview: Cannot preview in this file — the preview crashed / failed to build
Xcode Previews couldn’t build or run the view — compile errors elsewhere, a crash in preview data, or preview-specific environmen…
Two steps away (35)
TypeError: x is not a function
You called something as a function, but its value is not a function (it’s undefined, a string, an object…).
ReferenceError: x is not defined
Code refers to a variable or function name that doesn’t exist in the current scope.
Error: Objects are not valid as a React child
You tried to render a plain object (or a Promise/Date) directly in JSX; React can only render strings, numbers, elements and arra…
TypeError: 'NoneType' object is not subscriptable
You used `[ ]` on a value that is `None` — typically a function that returned nothing.
java.lang.ClassNotFoundException / NoClassDefFoundError
The JVM couldn’t find a class on the classpath at runtime.
java.lang.OutOfMemoryError: Java heap space
The JVM ran out of heap memory and garbage collection couldn’t free enough.
java.lang.IllegalArgumentException
A method rejected an argument value as invalid.
java.lang.ArithmeticException: / by zero
Integer division or modulo by zero.
Fatal error: Uncaught Exception: message in file.php:12
An exception was thrown and nothing caught it, so PHP stopped the script.
InvalidOperationException: Unable to resolve service for type 'X' while attempting to activate 'Y'
ASP.NET Core’s dependency injection container can’t build Y because one of its constructor dependencies (X) was never registered.
InvalidOperationException: Sequence contains no elements / more than one element
LINQ `First()`, `Single()`, `Last()` or `Max()` ran on an empty sequence (or `Single()` found several items).
Fatal error: Uncaught Error: Call to a member function x() on null
Code called a method on a variable that is null instead of an object.
The application was unable to start correctly (0xc000007b)
A program loaded a DLL of the wrong architecture (32-bit vs 64-bit) or a corrupted runtime library.
VCRUNTIME140.dll was not found / MSVCP140.dll is missing
The program needs the Microsoft Visual C++ 2015–2022 Redistributable, which isn’t installed (or is damaged).
Segmentation fault (core dumped)
A program accessed memory it wasn’t allowed to, and the kernel killed it with SIGSEGV (exit code 139).
java.lang.IllegalStateException
A method was called when the object wasn’t in the right state for it.
FATAL: the database system is in recovery mode
PostgreSQL crashed (often OOM-killed) and is replaying WAL to recover.
ArgumentOutOfRangeException: Index was out of range. Must be non-negative and less than the size of the collection
Code accessed a List/collection position that doesn’t exist (IndexOutOfRangeException for arrays).
error while loading shared libraries: libX.so.N: cannot open shared object file: No such file or directory
The program needs a shared library (.so) that isn’t installed or isn’t on the loader’s search path.
.NET: Stack overflow. / Process is terminated due to StackOverflowException
Infinite or very deep recursion exhausted the thread’s stack; .NET can’t catch it and terminates the process.
Thread 1: EXC_BAD_ACCESS (code=1, address=0x0)
The app accessed memory it shouldn’t — a dangling pointer, released object, unsafe pointer misuse, a data race, or infinite recur…
java.nio.file.AccessDeniedException: /path
The OS denied a file operation to the Java process.
System.InvalidCastException: Unable to cast object of type 'X' to type 'Y'
An explicit cast failed because the object’s runtime type isn’t the target type.
exec /usr/local/bin/docker-entrypoint.sh: exec format error
The container tried to run a binary built for a different CPU architecture (arm64 vs amd64) — or a script with a broken shebang /…
no matching manifest for linux/arm64/v8 in the manifest list entries
The image has no build for your CPU architecture — typically pulling an amd64-only image on an Apple Silicon Mac or ARM server.
cannot execute binary file: Exec format error
The program was built for a different CPU architecture or OS — e.g. an x86_64 binary on an ARM machine (Raspberry Pi, Graviton, A…
Kubernetes: OOMKilled (exit code 137)
The container used more memory than its limit, and the kernel killed it.
Blue Screen: MEMORY_MANAGEMENT (Stop code 0x0000001A)
Windows detected a severe memory-management error — commonly faulty RAM, unstable memory settings or a bad driver.
Killed / Out of memory: Killed process (Linux OOM killer)
The kernel ran out of memory and killed a process to recover — the program just prints “Killed” (exit code 137).
FATAL ERROR: Reached heap limit Allocation failed - JavaScript heap out of memory
The V8 heap hit its limit — a large build (webpack, tsc, Next.js) needs more memory, or the app leaks.
RangeError: Invalid string length
A string grew beyond the engine’s maximum length — usually runaway concatenation or huge JSON.stringify output.
MaxListenersExceededWarning: Possible EventEmitter memory leak detected. 11 listeners added
More than 10 listeners were added to one event — often a leak where listeners are added repeatedly.
SwiftUI: Modifying state during view update, this will cause undefined behavior
A @State/@Published value was changed while SwiftUI was computing a view’s body.
SwiftUI: Publishing changes from background threads is not allowed; make sure to publish values from the main thread
An ObservableObject’s @Published property was updated from a background thread.
Signing for "App" requires a development team. Select a development team in the Signing & Capabilities editor
No Apple developer team is selected for the target, so Xcode can’t sign the app.
Map another error
Popular: 4035004000xC000007BTypeErrorCritical error404NullPointerException