Error map
FileNotFoundException assembly Could not load file or assembly 'X, Version=…' or one of its dependencies
.NET · layer 4, Application & API
Centre: this error. First ring: errors it is linked with (11). 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 (11)
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.
java.lang.ClassNotFoundException / NoClassDefFoundError
The JVM couldn’t find a class on the classpath at runtime.
Failed to load module script: Expected a JavaScript module script but the server responded with a MIME type of "text/html"
A or dynamic import got HTML back instead of JavaScript.
HTTP Error 500.30 - ASP.NET Core app failed to start
IIS/Azure’s ASP.NET Core Module launched your app but it crashed during startup.
ChunkLoadError: Loading chunk 123 failed.
A lazily loaded JavaScript chunk couldn’t be downloaded — usually because a new deployment removed the old hashed files.
PHP still runs old code after deploy (OPcache not reset)
OPcache keeps serving cached bytecode, so changes uploaded to the server don’t take effect.
error NETSDK1045: The current .NET SDK does not support targeting .NET 8.0. Either target .NET 7.0 or lower, or use a version of the .NET SDK that supports .NET 8.0
The installed .NET SDK is older than the project’s TargetFramework.
The framework 'Microsoft.NETCore.App', version '8.0.0' (x64) was not found. You must install or update .NET to run this application
The machine doesn’t have the .NET runtime version the app was built for (framework-dependent deployment).
error NU1605: Detected package downgrade: X from 8.0.1 to 8.0.0. Reference the package directly from the project to select a different version
A direct reference requests a lower version than a dependency needs, and NuGet treats the downgrade as an error.
PlatformNotSupportedException: System.Drawing.Common is not supported on this platform
Since .NET 6, System.Drawing.Common only works on Windows; on Linux/macOS (including Docker) it throws.
Refused to execute script from 'x' because its MIME type ('text/html') is not executable
The browser fetched a script but the server labelled it text/html (usually an error page), so it refused to run it.
Two steps away (28)
Windows Error 0x80070643: Fatal error during installation
An MSI-based installer or update (often Defender definitions, .NET or the WinRE update KB5034441) failed during installation.
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).
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…
Gradle: Could not resolve all files for configuration / Could not resolve dependency
Gradle couldn’t download a dependency — wrong coordinates/version, missing repository, offline mode, or network/proxy issues.
PHP Fatal error: Uncaught Error: Class "X" not found
PHP couldn’t load the class — autoloading failed, the namespace is wrong, or the dependency isn’t installed.
ModuleNotFoundError: No module named 'x'
Python can’t find the module you import — it isn’t installed in the interpreter/virtualenv that’s running, or the import path is…
Azure App Service: ":( Application Error" / container didn’t respond to HTTP pings
App Service started your app but it crashed or never listened on the expected port.
SyntaxError: Unexpected token '<' (HTML served instead of JavaScript)
The browser loaded a .js file but received HTML (an error page or the SPA index.html).
Console: Refused to apply style from 'https://…/style.css' because its MIME type ('text/html') is not a supported stylesheet MIME type
The stylesheet URL returned something that is not CSS — usually a 404/HTML error page — and `X-Content-Type-Options: nosniff` mak…
HTTP 500 Internal Server Error
The server hit an unexpected condition — usually an unhandled exception or misconfiguration in the application.
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.
java.lang.ExceptionInInitializerError
A static initializer (static block or static field) threw an exception while the class was loading.
DOMException: Failed to execute 'querySelector' on 'Document': 'x' is not a valid selector
The CSS selector string is invalid — often an ID starting with a digit or containing special characters.
Module not found: Can't resolve 'fs' (Next.js / webpack 5)
A Node.js built-in (fs, path, crypto, net) is imported into code that runs in the browser bundle.
Module parse failed: Unexpected token. You may need an appropriate loader to handle this file type
Webpack found syntax it can’t parse because no loader is configured for that file (JSX, TypeScript, CSS, or modern syntax in node…
FastCGI sent in stderr: "Primary script unknown"
Nginx passed a script path to PHP-FPM that PHP-FPM couldn’t find — usually a wrong SCRIPT_FILENAME or root.
npm ERR! code ELIFECYCLE / Command failed with exit code 1
An npm script (build, start, test, postinstall) exited with an error. ELIFECYCLE is only the wrapper — the real error is printed…
gyp ERR! build error / node-gyp rebuild failed
A dependency with native C/C++ code couldn’t compile — missing build tools, Python, or an unsupported Node version.
COPY failed: file not found in build context / "/app/x": not found
The Dockerfile COPY refers to a path outside the build context, excluded by .dockerignore, or relative to the wrong directory.
java.lang.UnsupportedClassVersionError: class file version 61.0, this version of the Java Runtime only recognizes up to 55.0
Code compiled for a newer Java version is running on an older JVM.
npm ERR! code ERESOLVE — unable to resolve dependency tree
npm 7+ found conflicting peer dependency requirements and refuses to install a broken tree.
Error: Cannot find module 'x' (MODULE_NOT_FOUND)
Node can’t resolve the module path — the package isn’t installed, or a relative path/extension is wrong.
ImportError: cannot import name 'x' from 'y'
The module was found, but the name you’re importing from it doesn’t exist — usually a version change or a circular import.
Kubernetes: ImagePullBackOff / ErrImagePull
The node can’t pull the container image — wrong name/tag, missing registry credentials, or registry unreachable.
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 /…
Fatal error: Uncaught Error: Call to undefined function imagecreatefromjpeg()
The GD extension (or its JPEG/WebP support) isn’t installed for the PHP version serving the site.
Console: Failed to register a ServiceWorker: A bad HTTP response code (404) was received when fetching the script
The browser could not fetch, parse or install the service worker script, or the page is not allowed to register one (HTTPS and sc…
DevTools: Failed to load source map — Could not load content for https://…/app.js.map: HTTP error: status code 404
DevTools could not download the `.map` file that a script or stylesheet points to, so you see minified code instead of your sourc…
Map another error
Popular: 4035004000xC000007BTypeErrorCritical error404NullPointerException